CSR-20 & CSR-40, September 1999
Mechanical Diagnosis
8-5
Condition
Possible Cause
Remedy
Evaporator fan motor(s)
Unit on defrost
Check operating mode indicator lights
does not operate
Unit in Economy Mode (Frozen Load;
Check setpoint, indicator lights and
Null mode ONLY)
Program menu of
µ
P-D controller to verify
that Economy Mode is set to ON
Loose line connection
Tighten connections
Open motor internal thermal
Check for seized bearings or defective
overload protector
thermal overload protector. Repair or
replace as necessary
Defective motor
Replace motor
Defective low or high speed
Replace defective contactor
evaporator fan contactor
No low or high speed evaporator
Diagnose and replace output module or
fan output signal from controller
controller
output module
