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.
This
symptom
remain for 60 seconds at wh
time
the control circuit
willI
s
off and the external failure Ii
will
go on.
been
or
will
ich
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.
High
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
6Correct.
7. Adjust makeup control.
8. Replace fault relay.
IM
307
/
Page 21
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