3--2
© 2015 Mobile Climate Control
T-367 Rev. 05/2015
Table 3-1 General System Troubleshooting Procedures - Continued
INDICATION -
TROUBLE
POSSIBLE CAUSES
3.4 Abnormal Noise Or Vibrations - Continued
Condenser or evaporator fans Loose mounting hardware
Defective bearings
Blade interference
Blade missing or broken
3.5 No Evaporator Air Flow Or Restricted Air Flow
Air flow through coil blocked Coil frosted over
Dirty coil
Dirty f ilter
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
3.6 Expansion Valve Malfunction
Low suction pressure with high super
heat
Low refrigerant charge
Wax, oil or dirt plugging valve orifice
Ice formation at valve seat
Power assembly failure
Loss of bulb charge
Broken capillary tube
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
Side to side temperature difference
(Warm Coil)
Wax, oil or dirt plugging valve orifice
Ice formation at valve seat
Power assembly failure
Loss of bulb charge
Broken capillary
3.7 Heating Malfunction
Insufficient heating Dirtyorpluggedheatercore
Coolant solenoid valve(s) malfunctioning or plugged
Low coolant level
Strainer(s) plugged
Hand valve(s) closed
Water pumps defective
Auxiliary Heater malfunctioning.
No Heating Coolant solenoid valve(s) malfunctioning or plugged
Controller malfunction
Pump(s) malfunctioning
Safety device open
Continuous Heating Coolant solenoid valve stuck open
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