Thermo King MD-MT, Operator'S Manual

Page: 143 / 192

143
Electric Standby Diagnosis
Condition Possible Cause Remedy
Unit switch On— lights do not
come on Battery discharged Charge or replace battery
Dirty battery terminals Clean and retighten terminals
Fuse F1 blown Replace fuse F1
Unit switch On— but electric
motor does not run No standby power Provide power to unit; check power
at:
1. Power source
2. Power plug
3. Motor contactor hot side
4. Motor contactor load side
(contactor closed)
5. Overload relay
6. Motor terminals
Defective motor contactor Repair or replace motor contactor
Defective low oil pressure sensor Replace low oil pressure sensor
Overload relay tripping Check for shorted motor windings or
wires
Control circuit breaker open Reset circuit breaker and reset
alarm codes
Defective motor Replace motor
Batteries discharged Charge or replace batteries
Electric motor hums but does
not run Locked rotor (overload relay will
open after a period of time) Remove interference
Locked compressor Repair compressor
Defective clutch on engine (locked
up) Repair or replace clutch
Low line voltage or no voltage on
one leg Bring voltage up to within 10% of
motor rating