Dometic air troubleshooting

Although the most common air conditioner malfunctions result from faulty installation and poor service, failures may occur even in case of professional installation and adequate service procedures. The table below is indispensible if your Dometic air conditioner fails. It explains what could have caused a certain malfunction and also suggests actions that may solve the problem.

Dometic FreshJet 1100 air troubleshooting

ProblemCauseRemedy
Roof air conditioner constantly switches itself off.
Icing sensor has tripped.Outer temperature is too low or all air nozzles are closed.
No cooling capacityThe roof air conditioner is not set to cooling.
Set the roof air conditioner to cooling.
The ambient temperature is above 52 °C.The roof air conditioner is only designed for ambient tempera- tures of up to 52 °C.
The temperature set is higher than the room temperature.Select a lower temperature.
The ambient temperature is below 16 °C.The roof air conditioner is only designed for ambient tempera- tures above 16 °C.
One of the temperature sensors is defective.Contact an authorised workshop.
The vaporiser fan is damaged. The condenser fan is damaged.
Low air outputThe air intake section is clogged up.Remove any leaves and other dirt from the ventilation grilles of the roof air conditioner.
The blower is defective.Contact an authorised work- shop.
Water enters the vehicleThe condensation water drainage openings are clogged up.Clean the drainage openingsfor condensation water.
The seals are damaged.Contact an authorised work- shop.
Roof air conditioner does not switch on.No supply voltage (230 V^) connected.Check the power supply.
The voltage is too low (under 200 V).Contact an authorized workshop.
The voltage converter is defective. One of the temperature sensors is defective.
The electrical fuse of the power supply is too low.Check the electrical fuse of the power supply.
Roof air conditioner does not switch off.One of the temperature sensors isdefective. Contact an authorised workshop.
The electrical fuse of the power supply is too low.Check the electrical fuse of the power supply.

Dometic CABIN COMFORT air troubleshooting

FAULTPOSSIBLE REASONCORRECTION
Nothing works at allAir conditioner circuit breaker is off.Turn circuit breaker on at ship’s panel.
Wiring at terminal strip is incorrectly wiredCheck wiring diagram; correct if necessary
Fan runs but no water flowWater intake valve is closedOpen valve
Strainer or intake is pluggedClean strainer/intake
Hose collapsed, kinked or pinchedRepair/reroute hose
Pump relay panel may not be operating properlyCheck pump relay panel wiring diagram. With unit breakers and A/C pump breaker on, check input voltage to relay panel. If voltage is not present, a wiring problem exists back to the ship’s panel. With unit on, check voltage at signal terminals (1A & IB, 2A & 2B, etc.) If voltage is not present, a wiring problem exists back to the unit. With voltage present at both locations above, check output terminals to seawater pump. If voltage is not present, either: 1. Signal circuit is defective. Move to a spare circuit if available. 2. Triac is defective on seawater pump circuit.
Replace circuit board if above does not correct problem
Fan and Pump run, but no cooling or heatingSelector switch may not be in “Run” position, but rather in “Start” modeVerify switch setting
Compressor not running or trying to startThermostat may not be set properly, thus not signaling compressor to start.Turn counter-clockwise for warmer and clockwise for cooler
Wiring terminal to thermostat or selector switch may be disconnected.Check wiring schematic before reconnecting loose terminals.
Fan and Pump run, but no cooling or heatingSeawater intake valve may be closed.Open valve
Compressor operates for only short periods of time.Seawater strainer or intakes could be plugged.Check hoses from intake to pump, pump to condensing unit, and condensing unit to overboard to make certain that they have not collapsed, pinched, or kinked.
Water pump may be defective.Check voltage to pump, check pump head and impeller.
Fan blows, Pump & Compressor runs, but unit does not heat or cool enough.Dirty return air filterClean filter
Check for proper thermostat settingTurn counter-clockwise for warmer and clockwise for cooler
On heat setting, system takes fifteen minutes to stabilize. As the seawater becomes colder, the output of the system is reduced. Note that 45°F (7.2°C) seawater is the coldest recommended operating level.Give system time to stabilize. Verify seawater temperature.
On cooling, the thermostat may be set too cold or supply air may be short cycling causing the evaporator coil to freezeCheck thermostat setting and/or redirect supply air so that it is not directed into the return air stream.
Switch unit into heat until the ice melts. A unit low on refrigerant charge will cause evaporator icing.
Low voltage can cause the air conditioning system to cycle off before proper temperature is reachedCheck electrical supply source
Reduced water flowVisually check water flow overboard and if low take corrective action

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