Dometic SMX II Description And Installation Manual page 25

Problem: Erratic SMX operation
Possible Solution:
1. Perform a Factory Memory Reset.
2. Check CX/CXP cable and connections.
3. Check temperature sensor, cable and connection.
4. Replace keypad/display.
5. Replace Power/Logic board.
Warning
The Power/Logic board operates at 115VAC or 230VAC.
Make sure the power is off before removing the cover of
the Power/Logic box.
Problem: Air from the unit does not feel cool
Possible Solution:
1. Make sure control is set in Cool mode.
2. Check thermostat setting.
3. Confirm that the compressor is running.
4. Check solenoid valve to see that it is opening.
Problem: Compressor is not running
Possible Solution:
1. Check water flow.
2. Check compressor relay, triggers.
3. Check high and low pressure switches.
4. Check solid state relay.
Problem: Unit blows cool air, but fails to cool the cabin
Possible Solution:
1. Check air filter.
2. Check thermostat setting.
3. Check compressor for short-cycling.
Problem: Compressor cycles on and off
Possible Solution:
1. Check water flow.
2. Check high and low pressure switches.
3. Check temperature sensor to make sure it is installed
properly and not touching any metal surfaces.
4. Ensure that cooling unit's discharge air is not blowing
directly toward the return air grill.
L-0952 Operation
Problem: The cooling unit won't heat
Possible Solution:
1. Check that control is in Heat mode, and thermostat is set
properly.
2. Enable Aux Heat on the SMX control (if a Factory
Memory Reset is performed, Aux Heat will need to be
enabled).
3. Check the manual thermal overload on the cooling unit.
Problem: Water dripping inside cabin
Possible Solution:
1. Clean out condensate drain pan and fittings.
2. Clear blockage in drain hose.
3. Check downhill routing of hose.
4. Ensure that insulation around ducting is not compressed
or crimped.
Problem: Condensing unit has frost buildup
Possible Solution:
1. This might be a normal occurrence in the modulating
system operation. As cooling units shut off, the load on
the unit drops and the suction line can frost up. If all
cooling units are on, and there is a sufficient heat load,
the suction line should not be iced over.
2. Check system charge.
Contact an authorized Cruisair servicing dealer if the
problem continues, or for replacement parts.
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