|
Compressor will
not run |
| a) Main switch
open. Circuit breakers open |
a) Close switch |
| b) Fuse blown |
b) Check
electrical circuits and motor winding for shorts
or grounds. Investigate for possible
overloading. Replace fuse or reset
breakers after fault is corrected. |
| c) Thermal
overloads tripped or fuses blown |
c) Overloads are
auto. reset. Check unit closely when
unit comes back on line. |
| d) Defective
contactor or coil |
d) Repair or
replace |
| e)
System shut down by safety devices |
e)
Determine type and cause of shut-down and
correct it before resetting safety switch. |
| f) No cooling
required |
f) None. Wait
until unit calls for cooling |
| g) Liquid line
solenoid will not open |
g) Repair or
replace coil |
| h) Motor
electrical trouble |
h) Check motor
for opens, short circuit, or burnout |
| i) Loose wiring |
i) Check all wire
junctions. Tighten all terminal screws |
|
High Discharge
Pressure |
| a) Condenser
water insufficient or temperature too high |
a) Readjust water
regulating valve. Investigate ways to
increase water supply |
| b) Fouled
condenser tubes (water cooled condenser).
Clogged spray nozzles (evaporative condenser).
Dirty tube and fin surface (air cooled
condenser) |
b) Clean |
| c) Non-condensibles
in system |
c) Purge the non-condensibles |
| d) System
overcharged with refrigerant |
d) Remove excess |
| e)
Discharge shut off valve partially dosed |
e)
Open valve |
| f) Condenser
undersized* |
f) Check
condenser rating tables against the operation |
| g) High ambient
conditions |
g) Check
condenser rating tables against the operation |
|
Discharge
Pressure |
| a) Faulty
condenser temperature regulation |
a) Check
condenser control operation |
| b) Suction
shut-of valve partially closed |
b) Open Valve |
| c) Insufficient
refrigerant in system |
c) Check for
leaks. Repair and add charge |
| d) Low suction
pressure |
d) See Corrective
Steps for low suction pressure below |
| e)
compressor-operating unloaded |
e)
See Correction Steps for failure of Compressor
to load up below |
| f) Condenser too
large* |
f) Check
condenser rating table against the operation |
| g) Low ambient
conditions* |
g) Check
condenser rating tables against the operation |
| |
|
|
Suction
Pressure |
| a) Lack of
refrigerant |
a) Check for
leaks. Repair and add charge |
| b) Evaporator
dirty |
b) Clean
chemically |
| c) Clogged liquid
line filter-drier |
c) Replace
cartridge(s) |
| d) Clogged
suction line or compressor suction gas strainers |
d) Clean
strainers |
| e)
Expansion valve malfunctioning |
e)
Check and reset for proper superheat.
Replace if necessary |
| f) Condensing
temperature too low |
f) Check means
for regulating condensing |
| g) Compressor
will not unload |
g) See Corrective
Steps for failure of compressor to unload |
| h) Insufficient
water flow |
h) Adjust gpm |
|
Little or no
oil pressure |
| a) Clogged
suction oil strainer |
a) Clean |
| b) Excessive
liquid in crankcase |
b) Check
crankcase heater. Reset expansion valve
for higher superheat. Check liquid line
solenoid valve operation. |
| c) Oil
pressure gauge defective |
c) Repair or
replace. Keep valve closed except when
taking readings |
| d) Low-oil
pressure safety switch defective |
d) Replace |
| e) Worn oil pump |
e) Replace |
| f) Oil pump
reversing gear stuck in wrong position |
f) Reverse
direction of compressor rotation |
| g) Worn bearings |
g) Replace
compressor |
| h) Low oil level |
h) Add oil |
| i) Loose fitting
on oil lines |
i) Check and
tighten system |
| j) Pump housing
gasket leaks |
j) Replace gasket |
| k) Flooding of
refrigerant into crankcase |
k) Adjust thermal
expansion valve |
|
Motor overload
relays or circuit breakers open |
| a) Low voltage
during high load conditions |
a) Check supply
voltage for excessive line drop |
| b) Defective or
grounded wiring in motor or power circuits |
b) Replace
compressor motor |
| c) Loose power
wiring |
c) Check all
connections and tighten |
| d) High
condensing temperature |
d) See Corrective
Steps for high discharge pressure |
| e) Power line
fault causing unbalanced voltage |
e) Check supply
voltage. Notify power company. Do
not start until fault is corrected |
| f) High ambient
temperature around the overload relay |
f) Provide
ventilation to reduce heat |
| g) Failure of
second starter to pull in on part-winding start
system |
g) Repair of
replace starter or time delay mechanism |