Operating instructions

21
This program will address the most common system problems associated with the Duo-Therm Air Conditioners
supplied by The Dometic Corporation. Our intent is to provide you with a guideline of checks to make, should you
encounter one of the following symptoms.
1. MECHANICAL CONTROL
Unit does not run; no fan, no compressor.
2. ELECTRONIC CONTROL
Unit does not run; no fan, no compressor.
3. BIMETAL RELAY CONTROL
Unit does not run; no fan, no compressor.
4. MECHANICAL CONTROL
Fan operates; compressor will not come on (does
not hum).
5. ELECTRONIC CONTROL
Fan operates; compressor will not come on (does
not hum).
6. BIMETAL RELAY CONTROL
Fan operates; compressor will not come on (does
not hum).
7. MECHANICAL, ELECTRONIC & BIMETAL RELAY
CONTROL
Fan operates; compressor tries to start, cycles OFF
and hums again, or blows circuit breaker.
8. MECHANICAL, ELECTRONIC & BIMETAL RELAY
CONTROL
Fan operates; compressor runs for a short while,
cycles off, cycles back on, but doesn't run.
Operating Instructions 1D 49
AC voltage 1B 26
Breaker 3B 26
Selector switch 5D/A 53
Wiring 10B 30
Operating Instructions 2D 49
AC voltage 1B 26
Breaker 3B 26
Wiring 11B 30
Control board 5D/C 54
Main board 5D/D 56
Operating Instructions 3D 51
Voltage 1B 26
Breaker 3B 26
Thermostat 5D/B 53
Relay Board 5D/E 57
Wiring 10B 30
Selector Switch 5D/A 53
Thermostat 5D/B 53
Overload 6C 37
Compressor 5C 36
Wiring 11B 30
Overload 6C 37
Compressor 5C 36
Control board 5D/B 53
Main Board 5D/D 56
Wiring 12B 30
Thermostat 5D/B 53
Relay Board 5D/E 57
Overload 6C 37
Compressor 5C 36
AC voltage 1B 26
PTCR or start relay 4C 36
Start or run capacitor 2C/3C 35-36
Overload 6C 37
Compressor 5C 36
Short cycle 9C 38
Air Flow obstruction 10C 38
Condenser fan 12C/E 44
Overload 6C 37
Compressor 5C 36
Refrigerant system 13C 45
DUO-THERM AIR CONDITIONERS
SYMPTOM CAUSE REFER TO PAGE