FIGURE 13 Continued. TROUBLESHOOTING GUIDE
DISCHARGE
TEMPERATURE
1. Low refrigerant charge.
2. Low refrigerant flow.
3. Condenser water flow too lo
w .
re too
4. Condenser water temperatu
high.
1. Check charge.
2. Check superheat.
3. Check water strainer and val
positions.
4. Examine cooling tower
5. High suction superheat. 5. Faulty expansion valve(s).
DISCHARGE PRESSURE 1. Cooling tower problem.
2. Low condenser water flow.
3. Fouled, dirty tubes.
4. Refrigerant overcharge.
5. Warm chilled water (startup) I.
la. Check tower water bypass.
b Check tower operation.
2 Pump, strainer
3 Measure condenser water pr
sure drop
4. Check subcooling.
5 Water temperature.
6. Air in refrigerant system.
EXTERNAL FAILURE 1. Power interruption (restored
voltage dip.
)
or
2. Low water flow.
6. Overall temperature and
pressures
1. Relays R1 R2, R5, R7 will b
de-energized and open.
2a Check water valves.
b. Flow switch malfunction.
c. Water strainer dirty.
d. Fouled tubes
3. No water flow
4. Defective R7 relay.
5. Flow switch open.
6. Pump interlocks open.
7. Compressor starter
8 Power single phase.
3a. Pumps.
b. Valve position
c. Pump starters
d. Condenser pump relay.
4. Check relay operation
5. Circuit continuity.
6. Circuit continuity.
7a. Overloads tripped
b. Incomplete transition.
8a. Compressor motor.
b. MCR failure
1. The compressor starter has
energized but the compress
does not start. T h i s symptom
remain for 60 seconds at wh
time the control circuit w i l l s
off and the external failure Ii
will go on.
been
or
will
i c h
witch
ght
1a Starter and MCR relays
b. Disconnect or circuit breakt
open.
c O.L tripped
LOAD RECYCLE 1 Normal shutdown
2. Load recycle thermostat.
3. Anti recycle thermostat.
1 Chilled water temperature
satisfied.
2a. Setting drift
b. Loss of bulb charge.
3a. Time delay not yet timed o
4. Low source water temperatu,rere
(Templifier).
b. Too fast response to load
changes.
4. Source water temperature.
SURGEGARD 1. Dirty condenser.
2. H i g h pressure lift
1.
Condenser tubes
2 Water temperatures.
3. Refrigerant overcharge
4. Defective R5 relay
5. Low condenser water flow
6. Open thermistor circuit.
7. Cooling tower.
8 Faulty Surgegard relay
_
_
_
3. Discharge pressure
4 Relay action
5 Strainer, valves
6. Check circuit
7 Water level
8 Interchange Guardistor
Surgegard relays
ve
es-
ut
1. Adjust as required.
2. Adjust expansion valve
3. Clean strainer is dirty, open
valves if partially closed.
4. Adjust tower control as required.
5. Repair or replace.
la. Adjust or replace control
b. Clean or repair,
2. Repair, clean.
3. Clean tubes.
4. Adjust refrigerant charge.
5. Regulate flow to depress
temperature.
6. Purge air.
1. Push reset button
2a. Properly position valves.
b. Repair flow switch.
c. Clean strainer
d. Clean tubes.
3a. Repair or restart.
b. Open valves.
c. Reset OL; repair interlocks
d. Repair, replace.
4. Replace relay.
5. Correct switch action.
6. Repair, replace.
7a. Reset or recalibrate.
b. Reset or repair starter
8a. Call McQuay Service.
b. Repair or replace.
1 a. Repair as required.
b. Close switch or circuit breaker.
c. Reset
1. None required.
2a. Recalibrate control.
b. Replace LRT.
3a. Wart for 20 minutes off time
delay.
b. Adjust controls.
4 Check heat source
1. Clean.
2. Reduce difference between enter-
ing/leaving water temperatures.
3. Reduce refrigerant charge.
4. Replace.
5. Clean strainer, open valves
6 Correct.
7. Adjust makeup control.
8. Replace fault relay.
IM 307 / Page 21
