Dometic RM3962 Proplem.

[rampddc]

My unit has a (2013) Dometic RM3962 installed by the previously owner so no warranty. We've been out two times an the unit has failed on use each time.

It will start on both LP or electrical an will run for 10 to 12 hrs then shut down with a E3 Error. The unit cools down to - fridge 2c / freezer -5c

When I do the diagnostic test everything checks out ok.

Before I run out an buy a new controller is there anything else I should check?

What I did so far:

• The cooling unit looks ok, so I did a hard wire to the electric heater an ran it for 20hrs with the fridge getting down to -2c
• The thermistor is with spec's (8350 ohms)
• Both the AC & DC are ok.
• By pasted the Thermofuse
• Checked stack temp every 1hr ( Low 27c - High 41c )

The unit has a cooling fan runs off & on will the unit is working.


Any help will be appreciated.

[rampddc]

Found some help at Appliance Repair Forum, sharing the post here to help others with smiler problem. Appliance Repair Forum

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What you need to do is determine if the gas and electrical are being activated at all when the unit calls for cooling. Start the unit and wait for it to reach the set temperature. Disconnect the thermistor so that the unit thinks the temp has risen and calls for cooling.

Check that there is (or isn't) power going to the heating element. If no power see below. If it goes to gas see if the gas ignites and if it stays lit or goes out. If it goes out and keeps trying to reignite replace the thermocouple. If it just keeps sparking let me know and we can go from there.

Basically it sounds like the unit is not resetting and calling for cooling after the initial cool down. This can be a thermistor but not very often. It is almost always a control board. If nothing happens after you disconnect the thermistor cut the 120 power and wait a bit. Turn it back on and see if you get power to the element. If you do the board is definitely bad. If still nothing at the element kill the 12 volt power and see if that resets it. If it does then again the board is toast.

[rampddc]

Just a quick update.

Last Thursday I picked up my new controller and install it into the fridge. It ran for 22 hours using the house batteries and propane and everything seemed to be okay.

On the weekend we went out camping & while hooked up to shore power the fridge failed again. (2hrs 35mins)

After some choice words and a few more hours of searching online I did find a Domedic service manual, that talks about AC power on the DC line. The fridge controller will shut down if there's anything more than six AC volts detected.

When I metered the power supply I was getting spikes of 28 AC volts on the DC side.

It would seem that my converter is failing and putting out AC current along the DC line, to confirm I disconnected my inverter and ran the fridge off my solar panels/house batteries & the fridge ran for 46 hours without failing.

I have ordered a Progressive Dynamics PD9260CV Inteli-Power 9200 Series 60 Amp to replace my unit.

[VinceU]

Nice job!