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34 Part # 25000102
SERVICE DIAGNOSIS CHART
Symptom Cause Remedy
Compressor
Does Not Run
1.
2.
3.
4.
5.
6.
Motor Line open
Fuse blown
Tripped overload
Control contacts dirty or jammed in open position
Piston seized
Frozen compressor or motor bearings
1.
2.
3.
4.
5.
6.
Close starter or disconnect switch
Replace fuse
See electrical section
Repair or replace
Remove motor-compressor head, look for broken valve
and jammed parts
Repair or replace
Unit Short
Cycles
1.
2.
3.
4.
5.
6.
Control dierential set too close
Discharge valve leaking
Motor compressor
Refrigerant shortage
Refrigerant over charge
Cycling on high pres. cutout
1.
2.
3.
4.
5.
6.
Widen dierential
Replace valve plate
Check for high head pressure, tight bearings, seized
pistons, clogged air-cooled condenser
Repair leak and recharge
Remove some refrigerant
Check condenser / or non condensable in system
Compressor
Will Not Start -
Hums
Intermittently
1.
2.
3.
4.
5.
6.
7.
Improperly wired
Low voltage
Relay contacts not closing
Open circuit in start-winding
Stator winding grounded
High discharge pressure
Tight compressor
1.
2.
3.
4.
5.
6.
7.
Check wiring against diagram
Check main line voltage - determine location of voltage
drop
Check my operating manually. Replace relay if defective
Check stator leads. If leads are all right, replace stator
Check stator. If leads are all right, replace stator
Eliminate cause of excessive pressure
Check oil level. Correct binding
Unit Operates
Long Or
Continuously
1.
2.
3.
4.
5.
6.
Control contacts sticking in closed position
Insucient refrigerant in system
Dirty condenser
Air or non-condensables in system
Compressor inecient
Improper wiring
1.
2.
3.
4.
5.
6.
Clean points or replace control
Check for leaks. Repair and add charge
Clean condenser
Purge high point in system
Check valves and pistons
Check wiring and correct if necessary
Fixture
Temperature
Too High
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
Insucient refrigerant in system
Control set too high
Control wiring loose
Expansion valve or strainer plugged
Compressor inecient
Expansion valve set too high
Iced or dirty coil
Unit too small
Clogged or small refrigerant lines
Oil logged in system
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
Check for leaks. Repair and add charge
Reset control
Check wiring to control
Clean or replace
Check valves and pistons
Lower setting
Defrost or clean coil
Add unit or replace
Clear line or increase line size
Remove excessive oil, check refrigerant charge
High
Discharge
Pressure
1.
2.
3.
4.
5.
6.
Refrigerant overcharge
Non-condensables in system
Dirty condenser coil
High side restriction
Head pressure control setting
Fan not running
1.
2.
3.
4.
5.
6.
Remove the excess
Remove the non-condensables
Clean
Check all valves or remove restriction
Adjust controls
Check electrical circuit
Installation and Operations Manual