Read IM 224-2: Packaged Water Chiller WHR 7/12-120 Tons, Vintage C text version

S E Packaged water chiller

Type WHR 7!4 thru 120 tons `C' vintage

.

13600 industrial Park Blvd , P 0 Box 1551. Minneapolis, MN 55440

MOVING THE UNIT

The McQuay SEASONPAK water chiller is mounted on heavy wooden skids to protect the unit from accidental damage and to permit easy handling and moving. It is recommended that all moving and handling be performed with the skids under the unit when possible and that the skids not be removed until the unit is in the final location. When moving the unit, dollies or simple rollers can be used under the skids. Never put the weight of the unit against the condensers or receivers. In moving, always apply pressure to the base on skids only and not to the piping or shells. A long bar helps move the unit easily. Avoid dropping the unit at the end of the rol I. If the unit must be hoisted, it is necessary to lift from the skid. A spreader bar must be used to protect the control cabinet and other areas of the chiller (see drawing). Do not attach slings to piping or equipment. Move unit in the upright horizontal position at all times. Let unit down gently when lowering from the trucks or rollers.

LOCATION

Unit is designed for indoor application and must be located in an area where the surrounding ambient temperatures are 40F or above. A good rule of thumb is to place units where ambients are at least 5 degrees above the leaving water temperature. Because of the electric control devices, the units should not be exposed to the weather. A plastic cover over the

control box is supplied as temporary protection during transfer. A reasonably level and sufficiently strong floor is all that is required for the SEASONPAK water chiller. If necessary, additional structural members should be provided to transfer the weight of the unit to the nearest beams.

SPACE REQUIREMENTS FOR CONNECTIONS AND SERVICING

The chilled water piping for all units enters and leaves the cooler from the rear. A clearance of 3 to 4 feet should be provided for this piping and for replacing the filter-driers, for servicing the solenoid valves, or for changing the compressors. should it ever become necessary. The condenser water piping enters and leaves the shell from the ends. Work space must be provided in case water regulating valves are being used and for general servicing. Clearance should be provided for removing cooler tubes on one end of the unit as specified in Table 1. It is also necessary to leave a work area on the end opposite that used for replacement of a cooler tube. The minimum clearance requirement for control box door opening is 36 inches.

TABLE 1. MINIMUM CLEARANCE

MINIMUM CLEARANCE FOR COOLER TUBE REMOVAL MEASURED FROM CENTER LINE O F CHILLED WATER CONNECTION ON EITHER END UNIT SIZE 008C thru 015C 02OC thru 03OC 04OC thru 060C 070 and 080C 1 ooc 090C, 110C, 1 2 o c MINIMUM CLEARANCE 72" 96" 120" 108" 120" 132"

PLACING THE UNIT

The small amount of vibration normally encountered with the SEASONPAK water chiller makes this unit particularly desirable for basement or ground floor installations where the unit can be bolted directly to the floor. The floor construction should be such that the unit will not affect the

building structure, or transmit noise and vibration into the

structure. See Vibration Isolators section for additional mounting information. NOTE: On the WHR-070C thru -120C, four shipping brackets are used to secure compressor to base. Remove these and discard after unit is mounted and before unit is

started.

PAGE 3

CHI LLED WATER THERMOSTAT WHR-008C thru 060C - The chilled water thermostat is mounted inside the control console and the control bulb, capillary tubing and control bulb immersion well are attached to the unit with spring clips. The control bulb well must be field inserted in the first tee installed in the return water line as shown in Figure 3. The bulb well is supplied with a %" NPT male thread. Carefully unsnap the well from the holding clips, remove the retaining bushing and slowly remove the bulb from the well. Install into piping as indicated in Figure 3. When installing the bulb, carefully remove it from the well so as to not wipe off the heat conducting compound supplied in the well. After installing the well, carefully insert the bulb and seal it with the excess compound. Insert the retaining gasket and sealing bushing and clip or tape the cap tube to the water line. Care should be taken not to break or kink the charged capillary tubing. FIGURE 3. THERMOSTAT WELL INSTALLATION Sufficient cap tube length is provided for bulb insertion up to 15 feet from the unit; however, it is recommended that the bulb well be placed as close to the cooler inlet as possible. Insulate over thermostat well. CAUTION: The thermostat bulb should not be exposed to water temperatures above 125eF since this will damage the control. WHR-070C thru 120C - The chilled water thermostat is mounted inside the control console. The control bulb is mounted in a well, located in the return water connection to the unit. Care should be taken not to damage the sensor leadwires when working around the unit. It is also advisable to check the leadwire before running the unit to be sure that it is firmly anchored and not rubbing on the frame or any other component.

TO COOLER

WATER FLOW SAFETY SWITCH A water flow safety switch is required for all type WHR SEASONPAK chillers. The flow switch must be field installed and wired into the SEASONPAK water chiller control center as indicated on the drawings. The flow switch should be installed in a horizontal run in either the supply or return chilled water piping as follows: 1. Apply pipe sealing compound to only the threads of the switch and screw unit into D" x D" x 1" reducing tee (see Figure 6). The flow arrow must be pointed in the correct direction. 2. Piping should provide a straight length before and after the flow switch of at least five times the pipe diameter. 3. Trim flow switch paddle if needed to fit the pipe diameter. Make sure paddle does not hang up in pipe. CAUTION: Make sure the arrow on the side of the switch is oointed in the orooer direction of flow. The flow switch is designed to handle the control voltage and should only be connected according to the wiring diagram (see Wiring Diagram inside control box door).

FIGURE 4. FLOW SWITCH VIEW FROM END OF COOLER

FLOW

PAGE 6

CONDENSER WATER PIPING General For the best performance, the condenser water must enter the bottom connection of the condenser. Water cooled condensers may be piped for use with cooling towers, well water or heat recovery applications. Cooling tower applications s h o u l d b e m a d e w i t h consideration to freeze protection and scaling problems. For specific applications, contact cooling tower manufacturer for equipment characteristics and limitations. Head Pressure Control - Tower System Some means of controlling operating head pressure must be provided. Minimum condensing temperature allowed is 9OoF. Minimum entering tower condenser water temperature is 70°F. Typical systems are shown in Figures 5 and 6. In Figure 5, a three-way pressure actuated water regulating valve is used for cooling applications. In Figure 6, capacity of the cooling tower is controlled through damper and/or fan modulation. These typical systems, depending on the specific application, must maintain a constant condensing pressure, regardless of temperature conditions and must assure enough head pressure for proper thermal expansion valve operation. Note also that both systems assure full water flow to the tower. Head Pressure Control -Well Water System Where well water is used for condensing refrigerant, a direct acting water regulating valve is recommended (see Figure 7). The valve is normally installed at the outlet of the condenser. On shutdown, the valve will close and, in this way prevent water siphoning out of the condenser. Siphoning causes drying of the water side of the condenser and rapid build-up of fouling. When no valve is used, a loop at the outlet end is recommended (see Figure 7).

COOLING TOWER SYSTEMS FIGURE 5.

3 WAY WATER REGULATING .VALVES

FIGURE 6

PURGE

MAIN CONDENSER @ WATER SUPPLY FROM PUMP

BYPASS BALANCING VALVES OR COCKS

FIGURE 7. WELL WATER COOLING SYSTEM

LOOP REPUIRED WHEN NO REGULATING VALVE IS USED

MAIN NSER PUMP DIRECT ACTING WATER REGULATING VALVE

PAGE 7

SINGLE CONDENSER HEAT RECOVERY ARRANGEMENT 1

Single circuit heat recovery employs a standard water cooled chiller equipped with heavier electrical components a n d a 3 8 0 PSIG h i g h p r e s s u r e l i m i t s w i t c h . T h e s e modifications allow leaving condenser water temperatures of up to 125oF for building or process heating applications. A typical heat recovery arrangement will include a closed circuit cooling tower used to reject unwanted condenser heat to the outdoor ambient air. The cooling tower should be sized to reject all the condenser heat during summer design operation. This insures proper operation in the non heat-recovery mode. Use of a closed circuit tower is normally required in order to prevent fouling of heating coils in the heat recovery loop. Condenser water remains free of contamination from minerals and impurities normally contained in make-up water in an open cooling tower. If a closed circuit cooling tower is to be located in an ambient temperature below freezing, protection against coil and sump freeze-up must be provided. Coil freeze protection can be provided by using a glycol solution or by maintaining a heat load on the coil at all times and maintaining water flow through the coil. Sump water freeze protection can be provided by locating the spray water circulating pump and sump tank inside a heated space or by placing heating coils in the sump. Head pressure and water temperature are normally controlled by the tower capacity control. Adequate capacity control is usually obtained by fan cycling and regulating dampers located in the fan discharge. This will maintain a constant tower water temperature. Consult the closed circuit tower manufacturer for information on specific applications. An auxiliary heat source is necessary if the available condenser heat is not sufficient to satisfy all of the heat load. The auxiliary heat source must be located between the condenser and the heat load and the control should be interlocked with the closed circuit tower to prevent auxiliary heating while rejecting heat to the ambient. When the heating load is satisfied, a two position three-way valve is set to divert condenser water around the heat load and the auxiliary heat source. Whether operating in summer or winter, the chiller is always controlled by the cooling load and not the heating load. Typical Operation On a call for cooling, the chiller starts and hot condenser water flows through the diverting valve to the closed circuit cooling tower rejecting heat to the outdoors. The tower dampers modulate to maintain a proper entering condenser water temperature which will give efficient operation by means of the proportional controller T2 located in the outlet fluid line of the tower. When a heating load is sensed by mode switch T1, the three-way valve is switched to allow condenser water to flow through the heating circuit. The proportional controller T2 is also reset upwards to give the desired water temperature for heat recovery. The unused condenser heat will be rejected out through the closed circuit tower. If the condenser heat of rejection cannot satisfy the heating load after an appropriate delay, the auxiliary heat source will b e activated.

F I G U R E 8 . T Y P I C A L S I N G L E C O N D E N S E R (P E R

REFRIGERANT

C I R C U I T) H E A T

RECOVERY

CONDENSER DIVERTING VALVE

COOLER PUMP

COOLING LOAD

.

NOTE: THE SCHEMATICSHOWS ONE REFRIGERANT CIRCUIT. MODELS WITH TWO REFRIGERANT PAGE 8 CIRCUITS HAVE TWO CONDENSERS.

DUAL CONDENSER HEAT RECOVERY ARRANGEMENT 4

Dual condenser heat recovery chiller models have two water cooled condensers per refrigerant circuit. The upper condenser is the heat recovery condenser and is piped into the building's hot water system. The lower condenser is the tower condenser and is piped to an open cooling tower. Condensing is done in either the tower condenser or heat recovery condenser, or partial condensing is done in each. The tower and heat recovery water circuits are independent and do not intermix. This use of an open tower and the closed heat recovery loop prevents fouling of the building's heating system. A sub-cooling circuit is provided in the tower condenser to provide optimum cooling efficiency. When the unit is operating on maximum heat recovery, the cooling tower will be modulated down to its minimum capacity, usually about 5% of full capacity. This provides sub-cooling for the system during heat recovery operation. Water can be heated up to 1250F in the heat recovery condensers to satisfy a heating load. If all of the condenser heat of rejection cannot be used, the remainder is rejected out through the cooling tower. The cooling tower should be sized to reject all of the condenser heat during summer operation. Freeze protection for the cooling tower must be provided if it is to operate in below freezing temperatures. Adequate capacity control must be provided to maintain a constant water temperature leaving the cooling tower. Head pressure and water temperature are controlled by the tower capacity control. Fan cycling and modulating fan discharge dampers should

be used. Consult the cooling tower manufacturer for

information on specific applications. If the available condenser heat cannot satisfy all of the heat load, an auxiliary heat source must be provided. The

auxiliary heat source should be located between the heat recovery condenser and the heat load and interlocked with the cooling tower so that auxiliary heat is not being supplied unless the cooling tower is modulated down all the way. The chiller operation is always controlled by the building's cooling load and not the heating load. Typical Operation On a call for cooling the chiller starts. If a heating load is sensed by mode switch T1, the heat recovery water pump PI will start and the cooling tower dampers will modulate to control the heat recovery condenser by means of proportional temperature controller T3. If maximum heat recovery is required, the tower dampers close and the fans shut off. The tower will then provide only sub-cooling. If more heat is required than the heat recovery condensers can provide, the auxiliary heat source is activated. When mode switch T1 senses that a heating load no longer exists, the heat recovery pump PI shuts off and the cooling tower modulates to control the entering tower condenser water temperature by means of proportional controller T2 and a sensor located in the tower sump. Proportional controller T2 is set at a temperature lower than T3 to provide optimum efficiency.

FIGURE 9. TYPICAL

DUAL

CONDERSER (PER CI R C U I T)

HEAT

RECOVERY

COOLING TOWER

CONDENSER

COOLER PUMP

COOLING LOAD

NOTE: THE SCHEMATICSHOWS ONE REFRIGERANT CIRCUIT. HEAT RECOVERY WHR MODELS WITH TWO

REFRIGERANT CIRCUITS HAVE TWO HEAT RECOVERY CONDENSERS AND TWO TOWER CONDENSERS.

PAGE 9

REFRIGERANT PIPING

UNIT WITH REMOTE CONDENSER General For remote condenser application, such as an air cooled condenser, the chillers, with and without mounted receivers, are shipped containing a Refrigerant-22 holding charge. It is important that the unit be kept tightly closed until the remote condenser is installed, piped to the unit and the high side evacuated. Refrigerant piping, to and from the remote unit, should be sized and installed according to the latest ASHRAE Handbook. It is important that the piping be properly supported with sound and vibration isolation between tubing and hanger and that the discharge lines be looped at the condenser and trapped at the compressor to prevent refrigerant and oil from draining into the compressor discharge manifold. Looping the discharge line also provides greater line flexibility. The discharge gas valve(s), liquid line solenoid(s), filterdrier(s), moisture indicator(s), and thermostatic expansion valve(s) are all provided as standard equipment with the SEASONPAK water chiller whether installed with remote or factory mounted receivers. Liquid line shut-off valve must be added in the field on arrangement 2 units between the receiver and remote condenser (receiver outlet shut-off is factory installed). Liquid line shut-off valve must be added in the field on arrangement 3 between the liquid line filter/drier and remote condenser. After the equipment is properly installed, the unit may be charged with Refrigerant-22, then run at design load conditions, adding charge until the liquid line sightglass is clear, with no bubbles flowing to the expansion valve. Total operating charge will depend on the air cooled condenser used and the length of external piping, but generally will be equal to the water cooled charge shown in Table 15, pg. 18. NOTE: On the arrangement -2 and -3 units (units with remote condensers), the installer is required to record the refrigerant charge by stamping the total charge and the charge per circuit on the serial plate in the appropriate blocks provided for this purpose. SEASONPAK water chillers without condensers or with mounted receivers require field piping to a remote condenser of some type. The design of refrigerant piping when using air cooled condensers involves a number of considerations not commonly associated with other types of condensing equipment. The following discussion is intended for use as a general guide to sound, economical and trouble-free piping of air cooled condensers. Discharge lines must be designed to handle oil properly and to protect the compressor from damage that may result from condensing liquid refrigerant in the line during shutdown. Total friction loss for discharge lines of 3 to 6 PSI is considered good design. Careful consideration must be given for sizing each section of piping to insure that gas velocities are sufficient at all operating conditions to carry oil. If the velocity in a vertical discharge riser is too low, considerable oil may collect in the riser and the horizontal header, causing the compressor to lose its oil and result in damage due to lack of lubrication. When the compressor load is increased, the oil that had collected during reduced loads may be carried as a slug through the system and back to the evaporator, where a sudden increase of oil concentration may cause liquid slugging and damage to the compressor. Any horizontal run of discharge piping should be pitched away from the compressor approximately j/4" per foot or more. This is necessary to move by gravity any oil lying in the header. Oil pockets must be avoided as oil needed in the compressor would collect at such points and the compressor crankcase may become starved. It is recommended that any discharge lines coming into a horizontal discharge header rise above the center line of the discharge header. This is necessary to prevent any oil or condensed liquid from draining to the top heads when the compressor is not running. In designing liquid lines it is important that the liquid reach the expansion valve with a minimum of flash gas since this gas will reduce the capacity of the valve. Because "flashing" can be caused by a pressure drop in the liquid lines, the pressure losses due to friction and changes in static head should be kept to a minimum. A check valve must be installed in the liquid line in all applications where the ambient temperature can get below the equipment room temperature. This prevents liquid migration to the condenser, helps maintain a supply of refrigerant in the liquid line for initial start-up and keeps liquid line pressure high enough on "off" cycle to keep the expansion valve closed. On systems as described above, a relief valve or relief type check valve must be used in the liquid line as shown in piping systems (Figures 11 & 12) to relieve dangerous hydraulic pressures that could be created as cool liquid refrigerant in the line between the check valve and expansion or shut-off valve warms up. A relief device is also recommended in the hot gas piping at the condenser coil as shown in Figures 10, 11 and 12 on page 12. Systems With Receivers The liquid line from the condenser to the receiver MUST be sized for sewer flow operation (100 FPM/velocity or less) and MUST be sloped to the receiver with no traps in the line. Any shut-off valve in this line must have an orifice area equal to the inside area of the line. Free drainage in this line is essential to permit gas from the receiver to vent back to the condenser. Failure to adequately size and slope this line will force liquid to back up into the condenser causing high head pressure and bubbling sightglass. To guard against gas binding in the receiver and liquid build-up in the condenser coil, which are common to this arrangement, be certain that the receiver is located as far below the condenser outlet as possible. The liquid line should be free of any traps or loops and, if there are any horizontal runs, they should be pitched down toward the receiver.

PAGE 10

Typical Arrangements Figure 10, page 12, illustrates a typical piping arrangement involving a remote air cooled condenser located at a higher elevation than the compressor and receiver. This arrangement is commonly encountered when the air cooled condenser is on a roof and the compressor and receiver are on grade level or in a basement equipment room. In this case, the design of the discharge line is very critical. If properly sized for full load condition, the gas velocity might be too low at reduced loads to carry oil up through the discharge line and condenser coil. Reducing the discharge line size would increase the gas velocity sufficiently at reduced load conditions; however, when operating at full load, the line might be greatly undersized and thereby create an excessive refrigerant pressure drop. This condition can be overcome in one of the two following ways: 1. The discharge line may be properly sized for the desired pressure drop at full load condition and an oil separator installed at the bottom of the trap on the discharge line from the compressor.

2. A double riser discharge line may be used as shown in Figure1 1, page12. Line "A" should be sized to carry the oil at minimum load condition and line "B" should be sized so that at the full load condition both lines would carry oil properly. Notice in all illustrations that the hot gas line is looped at the bottom and top of the vertical run. This is done to prevent oil and condensed refrigerant from flowing back into the compressor and causing damage. The highest point in the discharge line should always be above the highest point in the condenser coil; it is advisable to include a purging vent at this point to release noncondensibles from the system. Figure 12 illustrates another very common application where the air cooled condenser is located on essentially the same level as the compressor and receiver. The discharge line piping in this case is not too critical. The principal problem encountered with this arrangement is that there is frequently insufficient vertical distance to allow free drainage of liquid refrigerant from the condenser coil to the receiver.

UNIT WITH FACTORY MOUNTED CONDENSER(S) Units with factory mounted condensers are provided with complete refrigerant piping and full operating refrigerant charge at the factory. There is a remote possibility on arrangement 1 units utilizing low temperature pond or river water as a condensing medium, and if the water valves leak, that the condenser and liquid line refrigerant temperature could get below the equipment room temperature on the off cycle. This could open the expansion valve and cause recycling pumpdown. This problem only arises during periods when cold water continues to circulate through the condenser and the unit remains off due to satisfied cooling load. If this condition is anticipated, units can be ordered with liquid line solenoid valves in place of the standard pilot duty solenoid valves. If this condition does occur: 1. Cycle off the condenser pump, or 2. Add in-line liquid line solenoid valve.

PAGE 11

FIELD WIRING - CONTROL Control circuits on all units are designed for 115 volt operation. A separate source of 20 amp, 115 volt AC power may be brought to terminals 100 and 112 (with terminal 112 on the ground side) to power the control circuit. On 208 volt power, leads from any line and neutral of the 208 volt system may be brought to terminals 100 and 112 to provide 120 volts to the control circuit. An optional factory mounted transformer is available to provide the correct control circuit voltage. All models include the necessary factory wiring to power the transformer. On models WHR-008 thru 030, however, the transformer power leads must be connected with the power supply leads to the line side of the circuit breaker CB1. On models WHR-040 thru 120 the transformer power leads are connected to the power block PB1. Six %" conduit knockout openings are provided for field wired options and are located on the left side of the control panel when facing the unit control panel doors. The terminal block FTB (field wiring) located in the control circuit side of the control box is to be used for all field wired options.

INTERLOCK WIRING -CONDENSER PUMP STARTER OR AIR COOLED

CONDENSER FAN STARTER

Provisions are made for interlocking a condenser pump starter or air cooled condenser fan starter (MA or MB) to cycle with the compressor(s). Coil voltage must be 115 volts with a maximum of 20 VA. On the 40 to 120 ton units the interlock can be used with either one or two condenser pumps or air cooled condensers. When one circuit is required, jumper terminals 107 and 108 and connect the starter between terminals 107 and 114. This will provide condenser pump or condenser fan operation when either compressor is operating. When two circuits are required, connect the starter from the first circuit between terminals 107 and 114. The starter for the second circuit must be connected between terminals 108 and 114. A flow switch is necessary on all units. It is also advisable to wire a chiller pump interlock in series with the flow switch for additional safety.

TYPICAL - McOUAY

INTERLOCK

SCHEMATIC

PANEL TERMINALS ___

FIELD DEVICES AND WIRING CHILLER FLOW CHILLER PUMP ' 1 SWITCH INTERLOCK to9 I10 *--.----- [email protected] COND. PUMP OR FANS STARTER I07 &-______-----a--- ---___-_-7 INSTALL THIS JUMPER WHEN SINGLE STARTER IS USED DUAL CIRCUIT UNITS WHR-040 THRU I20 ONLY i FANS STARTER --&-----____+

I

_

I

_

DUAL CIRCUIT UNITS (WHR-040 THRU 120 ONLY1 -_ I NOTE

I I

FOR ADDITIONAL INFORMATION. SEE UNIT WIRING DIAGRAMS.

PAGE 19

INTERLOCK WIRING - CONTROLLED OVERRIDE OF PUMP SHUTDOWN A standard feature on all WHR SEASONPAK water chillers is COPSTM(Controlled Override of Pump Shutdown), a system for interlocking the field supplied chilled water pump into the chiller control system. A relay R-21 is wired into the unit control circuit so that a time clock and/or ambient thermostat can be connected to a pair of terminals (102 and 103) inside the unit control panel. The time clock can energize a pump starter. Once the pump starts, the flow switch and/or pump interlock will close and energize that part of the control circuit that will allow the unit to start. This feature makes it possible to turn off the chilled water pump and the chiller during periods of non-occupancy or at other times when cooling is to be locked out. For recycling pumpdown without a demand for cooling, a pair of relays (energized by low pressure controls) are also wired into this circuit to start the pump, close the flow switch and pump down the unit. NOTE: If a time clock, ambient thermostat and/or remote on-off switch are not used, terminals 102 and 103 must be jumpered together before the unit will start.

TYPICAL INTERLOCK SCHEMATIC

1112

FIELD DEVICES AND WIRING TIF&T;\FCK AMBIENT &so-j f-_7 LOCKOUT -+---yj~--_~-_ . OFF

NOTES: I PUMP STARTER CONTACTS ON Rl9, R20, AND R21 ARE LIMITED TO 250 VOLTS MAXIMUM. 2. FOR ADDITIONAL INFORMATION, SEE UNIT WIRING DIAGRAMS.

SEQUENCE OF OPERATION The following sequence of operation is typical for WHR SEASONPAK units with some frequently used options. Special units may incorporate additional controls, but the basic sequence of operation will be similar. Typical wiring diagrams for all unit sizes are shown on pages 25 through 39. This sequence is written for a 4-compressor unit. When components that apply to the fourth compressor are referred to, the equivalent components for the third and second compressors of a 3- or 2-compressor unit are indicated in parentheses (). With the control circuit power on, system switch S3 closed, and manual pumpdown switches PSI and PS2 closed, 115 volt power is applied through control circuit fuse F1 to the crankcase heaters HTR1 through 4 (HTR3, HTR2) and also to the contacts of low pressure switches LPI and LP2. When the remote time clock or manual shutdown switches turn "on", COPS pump starter relay R21 is energized, closing contacts 1 and 3 to start the chilled water pump. Relay R21 contacts 4, 6, 7 and 9 in the thermostat circuit also close. With the flow switch closed, if freeze controls FS1 and FS2, high pressure controls HP1 and HP2 and compressor motor protectors MP1 through MP4 (MP3, MP2) do not sense an alarm condition, safety relays RI1 through R 14 (R 13 and R 12) are energized, applying power to the water temperature controller TC1. The unit will operate automatically in response to TC1. On a call for cooling, the temperature control thermostat TC1 energizes liquid line solenoid valve SV1, opening the valve and allowing refrigerant to flow into the evaporator. As refrigerant pressure builds up, low pressure control LP1 closes, energizing low pressure relay R19 which closes to energize contactor Ml, starting compressor number 1. If additional stages of cooling are required, temperature control thermostat TC1 energizes liquid line solenoid valve SV2 after time delay relay T D 1 has sequenced closed, to initiate the same starting sequence in refrigerant circuit number 2. On 3- and 4-compressor units, if additional cooling is still required, the third and fourth stages of temperature control thermostat TC1 energize the third and fourth compressors after time delays TD12 and TD13 have sequenced closed.

PUMPDOWN CYCLE As temperature control thermostat TC1 is satisfied, it opens its contacts, de-energizing liquid line solenoid valve SV1, causing the valve to close. When the compressor has pumped most of the refrigerant from the evaporator to the condenser, the low pressure control LPI opens, shutting down the compressor. PAGE 20 Should a closed solenoid valve allow refrigerant to leak to the low side of the refrigerant circuit during unit "off" time, the buildup in pressure will cause the low pressure control to close and energize the low pressure relay R19. This action will start the water pump, close the flow switch and start the compressor for pumpdown.

START-UP & SHUTDOWN

PRE START-UP

1. With main disconnect open, check all electrical connections in control panel and starter to be sure they are tight and provide good electrical contact. Although connections are tightened at the factory they may have loosened enough in shipment to cause a malfunction.

2. Check and inspect all water piping. Make sure flow

well is full of heat conducting compound, and that the bulb is secured with the retaining fitting. 7. Check compressor oil level. Prior to start-up, the oil level should cover at least one-third of the oil sightglass. 8. Check pressure drop across evaporator and condenser, and see that water flow is correct per the design flow rates. 9. Check the actual line voltage to the unit to make sure it is the same as called for on the compressor nameplate within f 10% and that phase voltage unbalance does not exceed 2%. Verify that adequate power supply and capacity is available to handle load. 10. Make sure all wiring and fuses are of the proper size. Also make sure all interlock wiring is completed per McQuay diagrams. 11. Verify that all mechanical and electrical inspections by code authorities have been completed. 12. Make sure all auxiliary load and control equipment is operative and that an adequate cooling load is available for initial start-up.

direction is correct and piping is made to correct connection on evaporator and condenser.

3. Open all water flow valves to the condenser and evapo-

rator.

4. Flush the cooling tower and system piping. Start

evaporator pump and manually start condenser pump and cooling tower. Check all piping for leaks. Vent the air from the evaporator and condenser water circuit as well as from the entire water system. The cooler circuits should contain clean, non-corrosive water.

5. If water regulating valves are provided, connect their

capillary to the manual valves provided on the condensers and open the manual valves.

6. Check to see that the water temperature thermostat is

installed in the entering water line, that the thermostat

START-UP 1. Open the compressor suction and discharge shut-off

valves until back seated. Always replace valve seal caps.

2. Open the manual liquid line shut-off valve. 3. Check to see that the unit circuit breakers are in the

turning on the time clock, ambient thermostat and/or remote on/off switch if the unit and chilled water pump are electrically interlocked by using the COPS method as described on page 15. 9. Check resets of all safety controls. 10. Switch the unit circuit breakers to on. 11. Start the system by pushing the system switch S3 to on. 12. Throw pumpdown switches PSI and PS2 to "auto" for restart and normal operation. 13. After system performance has stabilized, it is necessary that the "Compressorized Equipment Warranty Form" (Form No. 206036A) be completed to obtain full warranty benefits. This form is shipped with the unit and after completion should be returned to McQuay's Service Department through your sales representative.

"off" position.

4. Check to see that the pumpdown switches PSI and PS2

are in the "manual pumpdown" position and the control system switch S3 is in the "off" position.

5. Throw the main power and control circuit disconnects

to the "on" position.

6. Allow the crankcase heaters to operate for at least 8

hours prior to start-up.

7. Adjust the dial on the temperature controller to the

desired chilled water temperature.

8. Start the auxiliary equipment for the installation by

WEEKEND OR TEMPORARY SHUTDOWN

Move pumpdown switches PSI and PS2 to the "manual

pumpdown" position. After the compressors have pumped down, turn off the chilled water pump. NOTE: With the unit in this condition, it is capable of recycling pumpdown. To defeat this mode of operation,

simply move control system switch S3 to the "off"

position. It is important that the compressors pump down before

the water flow to the unit is interrupted to avoid freeze-up

in the evaporator.

START-UP AFTER TEMPORARY SHUTDOWN 1. Start the chilled water pump. "auto pumpdown" position. 3. Observe the unit operation for a short time, noting unusual sounds or possible cycling of compressors.

2. With the control system switch S3 in the "on" position, move the pumpdown switches PSI and PS2 to the

EXTENDED SHUTDOWN 1. Close the manual liquid line shut-off valves. 4. 5. Move the control service switch S3 to the "off" position. Close the suction and discharge shut-off valves on the

2.

3.

After the compressors have pumped down, turn off the

chilled water pump. Turn off all power to the unit.

compressor(s) and the liquid outlet valve(s) at the condenser(s) or receiver(s).

PAGE 40

6.

Tag all opened disconnect switches to warn against start up before opening the compressor suction and discharge valves.

7.

Drain all water from the unit evaporator and chilled water piping if the unit is to be shut down during the winter and exposed to below freezing temperatures.

START-UP AFTER EXTENDED SHUTDOWN 1. Inspect all equipment to see that it is in satisfactory operating condition. 2. Remove all debris that has collected on the surface of the condenser coils (remote condenser models). 3. Open the compressor suction and discharge valves until back seated. Always replace valve seal caps. 4. Open the manual liquid line shut-off valves. 5. Check circuit breakers: they must be in the "off" position. 6. Check to see that the pumpdown switches PSI and PS2 are in the "manual pumpdown" position and the control system switch S3 is in the "off" position. 7. Throw the main power and control circuit disconnects to the "on" position. 8. Allow the crankcase heaters to operate for at least 8 hours prior to start-up. 9. Start the chilled water pump and purge the water piping as well as the evaporator in the unit.

IO. Start the auxiliary equipment for the installation by

turning on the time clock, ambient thermostat and/or remote on/off switch if the unit and chilled water pump are electrically interlocked by using the COPS method.

11. Adjust the dial on the temperature controller to the

desired chilled water temperature. 12. Check resets of all safety controls. 13. Switch the unit circuit breakers to "on". 14. Start the system by pushing the system switch S3 to "on". CAUTION: Most relays and terminals in the control center are hot with S3 and the control circuit disconnect on. 15. Throw pumpdown switches PSI and PS2 to the "auto pumpdown position for restart and normal operation. 16. After running the unit for a short time, check the oil level in each compressor crankcase and for flashing in the refrigerant sightglass (see Maintenance section).

OPTIONAL CONTROLS

PART WINDING START (OPTIONAL) This option is available on units sizes 15 thru 120 tons to provide reduced in-rush starting. The part winding start timer TD1 is wired in series with the M3 contactor. On initial start Ml pulls in the first compressor winding and after one second TD1 closes, energizing M3 and the second compressor winding.

PART WINDING START OPTION

LINE (SEE NOTE)

COMPR. CONTACTOR (2n'J MOTOR WINDING) NOTE: LINE IS ONLY HOT WHEN THE UNIT CALLS FOR COMPRESSOR TO RUN

COMPRESSOR LOCKOUT CIRCUITS (OPTIONAL) This option locks out the compressor and prevents restarting for five minutes after previous shutdown. The R5 relay is de-energized with Ml and the normally-closed contacts 4 and 5 close and energize TD5. After five minutes, TD5 contacts 2 and 3 time close, permitting the thermostat to energize the solenoid valve on a demand for cooling. As soon as the compressor starts, R5 is energized and normally-open contacts 1 and 3 close, bypassing TD5 contact, permitting normal operation. The timer operation for the second compressor circuit is similar.

NOTES , LINE IS ONLY HOT WHEN FREEZE CONTROL AND HIGH PRESSURE CONTROL PERMIT SAFE OPERATION ZLINE IS ONLY HOT WHEN FLOW CONTROL AND S Y S T E M SWITCH(S31 ARE CLOSE0 COMPRESSOR LOCKOUT OPTION COMPR. LOCKOUT TIME DELAY R5 LINE I (SEE N O T E 2 1 4"5 -8,4_-

"

4[6 TO UNIT THERMOSTAT

PAGE 41

LOW AMBIENT START TIMER (OPTIONAL) This option is available on the -2 and -3 units to permit the compressor to start and build up suction pressure under low head conditions. This feature consists of a solid state normally-closed time delay TD9 wired in series with relay R9. These controls are both wired in parallel with the liquid line solenoid valve. When the solenoid valve is energized by the unit thermostat TC1-1, the low ambient start relay R9 is energized through the time delay TD9. The relay R9 normally-open contacts 4 and 2 close bypassing the low pressure control relay contact R 19 and the normally-closed contacts 4 and 5 open, removing the freeze safety from the circuit. After 2-314 minutes, the time delay will open and de-energize the relay. If the system has not built up enough evaporator pressure to close the low pressure control, the compressor will stop. The time delay can be reset to its normally-closed-position by moving the pumpdown switch PSI (PS2) to the open position. Moving the pumpdown switch back to the "on" position will again energize the relay for another attempt to start up. If the system has built up enough evaporator pressure, the compressor will continue to run.

LOW AMBIENT START OPTION FSI

LOW PRESSURE \ RELAY CONTACT LINE 6,2 (SEE NOTE 21

LOW AMBIENT START TIME DELAY

/

NOTES LINE IS ONLY HOT WHEN FREEZE CONTROL AND HIGH PRESSURE CONTROL PERMIT SAFE OPERATION 2 LINE IS ONLY HOT WHEN THE UNIT THERMOSTAT CALLS FOR COMPRESSOR TO RUN

ALARM BELL (OPTIONAL) This option is available and is factory installed with a 24volt alarm bell which can be remotely mounted. The bell is wired into the control circuit so that it will sound whenever there is a failure due to an evaporator freeze condition, excessive head pressure, motor overload or low oil pressure.

ALARM BELL TRANSFORMER ALARM BELL OPTION ALARM BELL

H O T G A S BYPASS (O P T I O N A L ) This option allows passage of discharge gas to evaporator cap on the bulb and turn the adjustment screw clockwise. permitting operation at lower loads than available with To lower the setting, turn the screw counterclockwise. Do compressor unloading. A solenoid valve in the hot gas not force the adjustment beyond the range it is designed bypass line is wired in parallel with the liquid line solenoid for, as this will damage the adjustment assembly. SV1. The hot gas bypass is wired in the first refrigerant The regulating valve opening point can be determined by circuit and the lead-lag switches are therefore eliminated. slowly reducing the system load while observing the suction The hot gas bypass option is also available for the second pressure. When the bypass valve starts to open, the refrirefrigerant circuit whereby the lead lag switches remain. gerant line on the evaporator side of the valve will begin to The pressure regulating valve is factory set to begin feel warm to the touch. opening at 58 PSIG (32F for R-22). This setting can be CAUTION: The hot gas line may become hot enough to changed by changing the pressure of the air charge in the cause injury in a very short time, so care should be taken adjustable bulb. To raise the pressure setting, remove the during valve checkout.

HOT GAS BYPASS PIPING DIAGRAM

HOT GAS BYPASS ADJUSTMENT RANGE

R E M O TE BULB AD J US TM ENT

RANGE

Solenoid Valve

External Equalizer ConnectIon to Suction

Side of Evapoator

Bypass Valve

Expansion Valve

30

30

1

40

I I I I I JO 70 60 90 60 TEYP roF1 AT BULB LC!CATlON

I 100

1 .I10

PAGE 42

OPERATION

During full load operation, check the compressor oil level. It should be at the center of the oil sightglass during operation. Check the refrigerant charge frequently at the moisture liquid indicator. A steady clear glass of liquid refrigerant indicates sufficient charge. The sightglass also indicates the moisture content of the refrigerant in the system.The color of the element in the glass indicates whether the system is wet or dry. Refer to the color table on face or cap of the indicator. If the indicator does not show a dry system after several hours of operation, the filter-drier element must be changed. Check the temperature control thermostat by observing operation at reduced loads. The thermostat is factory set for 44F leaving chilled water temperature when the entering temperature is 54F. Refer to Checking Controls section, below. Check voltage and amperage of the compressor motor. Adjust water regulating valve for discharge pressures between 200 and 230 PSIG for the most economical operating pressure. Close gauge valves at gauges when gauge readings are not required. This will prolong the gauge life.

CHECKING CONTROLS

All controls are checked and adjusted prior to leaving the factory. However, after the unit has operated satisfactorily for a reasonable length of time, a check of the operation and safety controls can be made as indicated below. OIL PRESSURE SAFETY SWITCH The oil failure pressure switch is activated by a low pressure differential between the oil pressure and the crankcase pressure. Upon start-up, the normally-closed pressure actuated contact of this control opens when the pressure differential increases to about 15 PSIG. If oil pressure does not reach this differential, the thermal time delay remains energized and opens a bimetallic safety contact, de-energizing the complete control circuit. If pressure reaches the prescribed differential within 120 seconds, the thermal time delay is de-energized and the control circuit remains closed. If, during the operation, the oil pressure differential falls below 10 PSIG, the thermal time delay is again energized and the control will shut down the compressor. To check the control, jumper the freezestat terminals L and M and trip the circuit breaker to the "off" position. Throw control circuit to "on" to pull in contactor. The contactor should drop out after approximately 120 seconds or less. After checking the control, wait approximately 2 to 3 minutes and then reset control manually. The compressor can then be started. Repeated successive operations of the control will require a longer period before it can be reset, since the bimetal will get hotter and will take more time to cool.

HIGH PRESSURE CONTROL The high pressure switch will shut down the compressor and close the liquid line solenoid valve when the compressor discharge pressure reaches 270 PSIG for water cooled units, or 380 PSIG for air cooled units. To check the control, slowly throttle the condenser inlet water or shut down the condenser fan. Observe the cut-out point. During testing, stand by the system switch to shut down the unit should the safety device malfunction. Be sure the gauges used are accurate. The water cooled condensers are supplied with a 450 PSIG relief valve and the discharge pressure during the test must be kept below 270 PSIG. For air cooled condenser operation, a relief valve set for 450 PSIG should be field supplied. The control can be manually reset at approximately 70 PSIG below the cutout point.

LOW PRESSURE CONTROL This pressure switch is connected to the low side of the system and its purpose is to shut down the compressor at the end of the pumpdown cycle. It will open at 35 PSIG and automatically reset at approximately 60 PSIG. The control can be checked by throwing the individual pumpdown switches to the manual position and observing the cut-out point of the gauge.

FREEZESTAT The freezestat is a pressure type control connected to the low side of the system and is set to shut down the system when the pressure drops low enough to be dangerous as far as cooler freeze-up is concerned. The control is factory set at 52 to 53 PSIG. When dropping to this point, the normally-open pressure actuated contacts of this control will close, energizing a 115 volt heater. This causes the normally-closed bimetallic relay switch of this control to open after a delay of approximately 60 seconds or less, stopping the compressor and closing the liquid line solenoid valve. The time delay prevents nuisance trip-out on momentary low suction pressure and permits the operation of the system on a "pumpdown cycle." The control must be checked while the system is operating. To check the control, install a voltmeter or neon test light across terminal T1 and T2 of the low pressure freeze control. There should be a voltage indication or the test light will glow, indicating the contacts are opened. Throw the pumpdown switch to the manual position and check the pressure at which the test light goes out or the voltmeter goes to zero. In actual operation, the compressor will shut down and the safety light will go out. The control can be manually reset in about two minutes.

THERMOSTAT The thermostats supplied on all packaged chillers are factory calibrated for use in the return water line to the cooler inlet. The thermostat bulb is installed in a well in the return water line in order to be more stable under temperature changes due to load conditions. The return water does not change temperature as rapidly as the outlet because of the "flywheel effect" of the total water system. This results in stable control of the outlet water temperature. Normally

PAGE 43

the thermostat requires no adjustment in the field other than the dial setting for the required control point. The control will maintain an average leaving water temperature corresponding to dial setpoint throughout the loading and unloading sequence of the unit. It should be realized, however, that there will be a fluctuation in the leaving water temperature as the unit cycles, unloads and loads. The thermostat will provide satisfactory control over a chilled water range of 8 - 12OF. Beyond these extremes special controls will be required to provide best system performance. On a two-stage thermostat, the dial setting indicates the average leaving water temperature that the control will maintain. At a 44F setting, the high stage should open at approximately 51 F return water and 41 F leaving, based on 10F cooling range. The low stage will open at 46F return or 41F leaving (5F TD or 50% capacity). As the water warms up, the low stage should cut in at approximately 49F which is the inlet and outlet temperature with the unit off and the high stage should operate at 54F return or 49F leaving. These settings may be checked by operating the unit and slowly regulating the load from full to minimum and return. It may then be necessary to adjust the dial and/or differential between switches to obtain these values. COMBINATION Each refrigerant circuit is furnished with a full flow replaceable core type filter-drier. The core assembly consists of one or more cores held tightly in the shell in a manner that allows full flow without bypass. CAUTION: Pump out refrigerant before removing end flange for replacement of core. A condenser manual liquid line valve is provided for

CAUTION: Response time on the two-stage thermostat is slow; consequently, approximately 5 minutes must be allowed for bulb response (after attaining system steadystate operation) before any or each adjustment to thermostat is made. On the four-stage thermostat the dial setting indicates the cut-in point of the first stage. With the dial set at 46%F, the first stage will actuate at 46%F, the second stage at 49F, the third stage at 51%F and the fourth stage at 54F. On a temperature drop, the fourth stage will open at a return water temperature of 51%F, the third stage at 49F, the second stage at 46%F and the unit will shut off at 44F return water. These settings may be checked by operating the unit and slowly reducing the load. The four-stage thermostat has a fixed switch differential and fixed differential between switches. DO NOT make any adjustments other than the dial as this is a preset precision control. OPERATION LIMITS - Do not operate unit at a thermostat setting below 42OF or above 50°F as serious problems may result such as cooler freezeup or compressor overheating.

FILTER-DRIER isolating the charge in the condenser, but also serves as the point from which the liquid line can be pumped out. With the line free of liquid, the filter-drier core can be easily replaced. NOTE: On the -2 and -3 units the filterdrier cores are shipped separately. The installer must install these cores before starting the unit.

LIQUID SIGHTGLASS AND MOISTURE INDICATOR The color of the moisture indicator is an indication of the dryness of the system and is extremely important when the system has been serviced. Immediately after the system has been opened for service, the element may indicate a wet condition. It is recommended that the equipment operate for about 12 hours to allow the system to reach equilibrium before deciding if the system requires a change of drier cores. Bubbles in the sightglass to expansion valve at constant full load conditions indicate a shortage of refrigerant, a plugged filter, or a restriction in the liquid line. However, it is not unusual to see bubbles in the sightglass during changing conditions.

THERMOSTATIC EXPANSION VALVE The expansion valve performs one specific function. lt keeps the evaporator supplied with the proper amount of refrigerant to satisfy the load conditions. The sensing bulb of the expansion valve is installed in the closest straight run of suction line from the cooler. The bulb is held on by clamps around the suction line and is insulated to reduce the effect of surrounding ambient. In CRANKCASE The compressors are equipped with crankcase heaters. The 15 HP and smaller model compressors have heaters installed externally below the crankcase. The 20 HP and larger model compressors have heaters inserted into the crankcase. The function of the heater is to keep the temperature in the crankcase high enough to prevent refrigerant from migrating to the crankcase and condensing in the oil during case the bulb must be removed, simply slit the insulation on each side of the bulb, remove the clamps and then remove the capillary tubing that runs along suction line from the valve. The power element is removable from the valve body without removing the valve from the line. This requires pumpdown. HEATERS off-cycle. When a system is to be started up initially in cold ambient, the power to the heaters should be turned on for some time (at least 8 hours) before the compressor is started. The crankcase should be up to about 80F before the system is started up, to minimize lubrication problems on liquid slugging of compressor on start-up.

WATER COOLER The water cooler is of the direct expansion type with removable internally finned tubes and heavy terneplate baffles. The copper tubes are individually rolled into heavyduty, steel tube sheets and sealed by a steel refrigeration head.

PAGE 44

The water connection nozzles which enter and leave the shell are on the same side of the unit. No special attention is required for the cooler except that clean, filtered water should be supplied.

CONDENSER The condenser is of the shell-and-tube type with water flowing through the tubes and refrigerant in the shell. External finned copper tubes are rolled into steel tube sheets. Integral subcoolers are incorporated on 20 ton and larger Arrangement 1 units. Arrangement 4 units have integral subcoolers only in the tower condensers. All condenser are equipped with 450 PSIG relief valves.

SERVICE & MAINTENANCE

To assure smooth operation at peak capacity and to avoid damage to package components, a program of periodic inspections should be set up and followed. The following items are intended as a guide to be used during inspection and must be combined with sound refrigeration and electrical practices to assure trouble-free performance. The liquid line sightglass/moisture indicator on all circuits must be checked to be sure the glass is full and clear and the moisture indicator indicates a dry condition. If the indicator shows that a wet condition exists or if bubbles show in the glass, even with a full refrigerant charge, the filter-drier element must be changed. Water supplies in some areas may tend to foul the watercooled condenser to the point where cleaning is necessary. The fouled condenser will be indicated by an abnormally high condensing pressure and may result in nuisance tripouts. To clean the condenser, a chemical descaling solution should be used according to the manufacturer's directions. Systems with remote air-cooled condensers require periodic cleaning of the finned surface of the condenser coil. Cleaning may be accomplished by using a cold water spray, brushing, vacuuming, or high pressure air. No tools should be used that could damage the coil tubes or fins. A lead-lag switch is provided on all multiple compressor models to permit even distribution of wear on the compressors. This switch should be turned on an annual basis. The compressor oil level must be checked periodically to be sure the level is at the center of the oil sightglass. Low oil level may cause inadequate lubrication and oil failure switch trip-out. If the oil level is low and oil must be added, use Suniso 3G.

CONTROL CENTER ELECTRICAL The electrical control center is relatively easy to service since indicator lights are provided to show unit status. Determine that the problem is actually in the control panel before proceeding. By referring to the schematic wiring diagrams, the trouble can be isolated to a particular section of the panel. WARNING: Warranty is voided if wiring is not in accordance with specifications. A blown fuse or tripped protector indicates a short ground or overload. Before replacing fuse or restarting compressor, the trouble must be found and corrected. It is important to have a qualified control panel electrician service this panel. Unqualified tampering with the controls can cause serious damage to equipment and void the warranty.

SERVICE

The following steps should be taken prior to attempting any service on the control center: 1. Study the wiring diagram so that you understand the operation of the SEASONPAK water chiller. 2. Before investigating trouble in the control center, check for burned out light bulbs by testing across the appropriate terminals. CAUTION: The panel is always energized to g r o u n d even though the system switch is off. If it is necessary to de-energize the complete panel including crankcase heaters, pull main disconnect. If motor or compressor damage is suspected, do not restart until a qualified serviceman has checked the unit.

OPERATING LIMITS

l

Maximum allowable condenser water pressure is 150 PSIG. l Maximum allowable cooler water pressure is 150 PSIG. l Maximum leaving condenser water temperature is 125oF. This corresponds to 320 PSIG head pressure. l Maximum allowable water temperature to cooler in a non-operating cycle is IOOoF. Maximum entering water

temperature for operating cycle is 9OoF (during system changeover from heating to cooling cycle). l Minimum leaving water temperature from the cooler without freeze protection is 42OF. l Minimum entering tower condenser water temperature is 7OoF.

PAGE 45

TABLE 15. TROUBLE SHOOTING CHART

I

PROBLEM

C ompressor will not run Circuit b) Fuse

POSSIBLE CAUSES

a) Main switch open breakers blown open a)

POSSIBLE CORRECTIVE STEPS

Close switch b ) C h e c k electrical c i r c u i t s a n d m o t o r winding for shorts or grounds. fault unit is Investigate fuse corrected back on line for possible overloading. after when Replace or reset

breakers c) d) Thermal blown Defective devices f) h) No cooling required trouble g) Liquid line solenoid will not open Motor electrical wiring contactor or coil e) System shut down by safety overloads t r i p p e d or f u s e s closely

c) O v e r l o a d s a r e a u t o . r e s e t . C h e c k u n i t comes d) R e p a i r o r r e p l a c e e) D e t e r m i n e t y p e a n d c a u s e o f s h u t - d o w n a n d correct it before resetting safety switch f) None. Wait until unit calls for cooling g) Repair or replace coi I h) Check motor all for opens, short circuit, all or burnout

i) L o o s e

i) C h e c k

wire strews

junctions.

Tighten

terminal Compressor vibrating noisy or a) Flooding of refrigerant into crankcase *b) I m p r o p e r piping support o n disa) Check

setting

of

expansion

valve

b) R e l o c a t e , a d d , o r r e m o v e h a n g e r s c) R e p l a c e

charge or liquid line c) Worn compressor High Discharge Pressure a) b) Condenser Fouled cooled nozzles cooled c) *d) System closed *f) Condenser undersized conditions f) C h e c k the *g) H i g h ambient g) the condenser rating tables tables against against operation operation water insufficient tubes or

a) b)

Readjust vestigate Clean

water ways

regulating to increase

valve. water

InSupply

temperature too high condenser condenser) (waterspray Clogged

(evaporative condenser). in

condenser).

Dirty tube and fin surface (air Non-condensibles shut system with valve refrigerant partially c) P u r g e e) Open the valve non-condensibles

overcharged off

d) R e m o v e

excess

e) D i s c h a r g e

C h e c k condenser r a t i n g

l

Low Discharge Pressure a) b) c)

h.) Receiver gas bound

h.) Check for proper liquid line size & i n s t a l l a t i o n from condenser. temperature a) Check condenser control operation b) Op e n v a l v e c) Check for leaks. Repair and add charge d) unloaded See Corrective below Steps for failure table of cornthe Corrective Steps for low suction pressure

Faulty Suction closed

condenser shut-off

regulation valve partially in system

Insufficient

refrigerant pressure operating large

d ) L ow s u c t i o n e) Compressor

e) S e e f) g)

pressor t o l o a d u p b e l o w * f ) Condenser too Check Check the High Suction Pressure a) b) c) Excessive Expansion Compressor load valve overfeeding open unloaders condenser condenser rating rating against operation

*91 I- ow a m b i e n t c o n d i t i o n s

tables

against

operation

a) Reduce load or add additional equipment b) C h e c k c) See remote to bulb. Steps load Regulate below up superheat failure of Corrective for

c o mp r e s s o r Low Suction Pressure a) b) Lack of refrigerant dirty line gas filter-drier strainers e) C h e c k and if liquid suction valve

a) Check for leaks. Repair and add charge b) c) d) Clean Clean chemically. cartridge(s) strainers reset for proper superheat. Replace

Evaporator

c) C l o g g e d pressor e)

d ) C l o g g e d s u c t i o n l i n e o r comExpansion malfunctioning

Replace *Remote condenser models

necessary.

PAGE 46

TABLE 15 (Can't.) TROUBLE SHOOTING CHART

PROBLEM Low S u c t i o n P r e s s u r e

Continued)

POSSIBLE CAUSES

f) Condensing temperature too low g) C o m p r e s s o r wil h) Insufficient Defective Unloader capillary d) Stages Erratic

POSSIBLE CORRECTIVE STEPS

f) C h e c k means temperature g) See for regulating for condensing of compresCorrective gpm. Steps failure

I

not

unload

sor to unload water flow control defective h) Adjust

Compressor w i l l n o t load or load up

a) b)

C)

capacity

a) Replace b) R e p l a c e c) Replace

mechanism tube set for

Faulty thermostat stage or broken not application

d) R e s e t t h e r m o s t a t s e t t i n g t o f i t a p p l i c a t i o n a) b) Replace Adjust gpm.

Compressor Loading-Unloading Intervals t o o short

a)

water

thermostat flow

b) I n s u f f i c i e n t

water

Little or no oil pressure

a)

Clogged

suction liquid

oil in

strainer crankcase

a) b)

Clean Check line crankcase heater. Reset expansion liquid v a l v e for h i g h e r solenoid or when superheat. Keep Check

b) Excessive

valve taking

operation valve closed reading

c) O i l d)

pressure

gouge

defective. switch

c) R e p a i r except

replace.

Low-oil

pressure

safety

d) Replace e) R e p l a c e

defective e) Worn oil pump f) Oil pump wrong g) W o r n h) L o w i) L o o s e reversing geor stuck in position bearings oil level on oil lines into fitting of g) Replace h) A d d o i l i) C h e c k I) Adjust and tighten system valve k) R e p l a c e g a s k e t thermal expansion compressor f) R e v e r s e direction of compressor rotation

k) P u m p h o u s i n g g a s k e t l e a k s I) F l o o d i n g refrigerant crankcase Compressor l o s e s o i l a) Lock of refrigerant

a ) C h e c k f o r l e a k s and r e p a i r . refrigerant b) Check riser sizes

Add

l

d)

b) Velocity in risers too low

*c) O i l t r a p p e d i n l i n e Excessive blow-by M t r overload relays or oo rcuit breakers open a) L o w v o l t a g e d u r i n g h i g h l o a d conditions b) D e f e c t i v e o r g r o u n d e d w i r i n g i n motor c) L o o s e d) H i g h or power circuits power wiring temperature compression ring

c) C h e c k p i t c h o f l i n e s a n d r e f r i g e r a n t velocities d) Replace compressor

a)

Check drop

supply

voltage

for

excessive

line

b)

Replace

compressor-motor and tighten discharge p o w e r comis corrected heat delay

C) C h e c k all c o n n e c t i o n s pressure

condensing

o d) See Corrective Steps f r high e) C h e c k supply pony. Do not f) Provide voltage. start to Notify fault reduce

e) P o w e r l i n e f a u l t c a u s ing unbalanced vo ltoge f ) H i g h ambient the g) overload of Failure temperature relay starter to pull around

until

ventilation

second

g) Repair or replace starter or time mechanism a ) A d d f a c i l i t i e s s o that within allowable valve b) c) Open conditions

in on part-winding start system Compressor t h e r m a l protector s w i t c h open a) Operating ditions b) D i s c h a r g e valve c) B l o w n Freeze p r o t e c t i o n opens valve partially gasket low shut plate too beyond d e s i g n con-

ore

limits

R ep l a c e gasket to 42F or above pressure"

a) T h e r m o s t a t b) L o w water

set flow

a) R e s e t

b ) Adjust gpm. c) S e e "L ow s u c t i o n

c) Low suction pressure * R e m o t e condenser models

PAGE

47

IN-WARRANTY RETURN MATERIAL PROCEDURE

COMPRESSOR Copeland Refrigeration Corporation has stocking wholesalers who maintain a stock of replacement compressors and service parts to serve refrigeration contractors and servicemen. When a compressor fails in warranty, contact your local sales representative, or McQuay Warranty Claims Department at the address on the cover of this bulletin. You will be authorized to exchange the defective compressor at a Copeland Wholesaler, or an advance replacement can be obtained. A credit is issued to you by the wholesaler for the returned compressor after Copeland factory inspection of the inoperative compressor. If that compressor is out of Copeland's warranty, a salvage credit only is allowed. Provide McQuay with full details: McQuay unit model and unit serial numbers. Include the invoice and the salvage value credit memo copies and we will reimburse the difference. In this transaction, be certain that the compressor is definitely defective. If a compressor is received from the field that tests satisfactorily, a service charge plus a transportation charge will be charged against its original credit value. On all out-of-warranty compressor failures, Copeland offers the same field facilities for service and/or replacement as described above. The credit issued by Copeland on the returned compressor will be determined by the repair charge established for that particular unit.

COMPONENTS OTHER THAN COMPRESSORS Material may not be returned except by permission of authorized factory service personnel of McQuay Inc. at Minneapolis, Minnesota. A "Returned Goods" tag will be sent to be included with the returned material. Enter the information as called for on the tag in order to expedite handling at our factories and prompt issuance of credits. The return of the part does not constitute an order for replacement. Therefore, a purchase order must be entered through your nearest McQuay representative. The order should include part name, part number, model number, and serial number of the unit involved. Following our personal inspection of the returned part, and if it is determined that the failure is due to faulty material or workmanship, and in warranty, credit will be issued on customer's purchase order. All parts shall be returned to the pre-designated McQuay factory, transportation charges prepaid.

Information

IM 224-2: Packaged Water Chiller WHR 7/12-120 Tons, Vintage C

48 pages

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