4--2
T--304
04/08
Table 4--1 General System Troubleshooting Procedures -- Continued
INDICATION --
TROUBLE
POSSIBLE CAUSES
REFERENCE
SECTION
4.4 Abnormal Noise Or Vibrations -- Continued
Condenser or evaporator fans Loose mounting hardware
Defective bearings
Blade interference
Blade missing or broken
Check/Tighten
Replace
Check
Check/Replace
4.5 No Evaporator Air Flow Or Restricted Air Flow
Air flow through coil blocked Coil frosted over
Dirty coil
Dirty filter
Defrost coil
Clean
Clean/Replace
No or partial evaporator air flow Motor(s) defective
Motor brushes defective
Evaporator fan loose or defective
Fan damaged
Return air filter dirty
Icing of coil
Fan relay(s) defective
Safety device open
Fan rotation incorrect
Repair/Replace
Replace
Repair/Replace
Repair/Replace
Clean/Replace
Clean/Defrost
Check/Replace
1.5
Check
4.6 Expansion V alve Malfunction
Low suction pressure with high
superheat
Low refrigerant charge
W ax, oil or dirt plugging valve orifice
Ice formation at valve seat
Power assembly failure
Loss of bulb charge
Broken capillary tube
5.8
Check
4.6
Replace
Replace
5.16
Low superheat and liquid slugging
in the compressor
Bulb is loose or not installed.
Superheat setting too low
Ice or other foreign material holding valve open
5.16
5.16
Side to side temperature differ-
ence (W arm Coil)
W ax, oil or dirt plugging valve orifice
Ice formation at valve seat
Power assembly failure
Loss of bulb charge
Broken capillary
Check
5.7
Replace
Replace
5.16
4.7 Heating Malfunction
Insufficient heating Dirty or plugged heater core
Coolant solenoid valve(s) malfunctioning or plugged
Low coolant level
Strainer(s) plugged
Hand valve(s) closed
W ater pumps defective
Auxiliary Heater malfunctioning.
Clean
Check/Replace
Check
Clean
Open
Repair/Replace
Repair/Replace
No Heating Coolant solenoid valve(s) malfunctioning or plugged
Controller malfunction
Pump(s) malfunctioning
Safety device open
Check/Replace
Replace
Repair/Replace
1.5
Continuous Heating Coolant solenoid valve stuck open 5.12
To Next Page
Loading...
