DOMETIC RMD8555 fridge not working on electric

[chris]

For the last 2 anual services of our van I told the dealer the electric on the RMD8555 Dometic fridge not cooling on electric. Its a 2014 model. They test it at the dealer and say its working after keeping it there several days and nothing wrong.. This weekend we used the electric again and it stopped working overnight after an initial startup that seemed ok. It works great on gas and all the lights and symbols work. There is no error message either. Does anyone know what this fault is as it stops working after about 12 hours? We make sure it is very flat too before testing. Thanks in advance. Chris

[stevec176]

When you say 'it stops working' what exactly do you mean? Are you saying it doesn't cool, is the internal light on? Please try and be as specific as you can.

I had a problem with my dometic fridge/ freezer and it went back to the dealers because the fridge kept defrosting and then freezing up along the drain channel on the back wall. They kept telling me it was working normally, in the end I took photos of the freezing and they replaced the fridge/freezer.

[chris]

it seems to cool the interior and temperature was about 10 degrees inside {not good) but in the morning the temperature is 20 degrees so obviously not coooling

[Robinhood]

...AFAIK, that fridge uses the same temperature sensor (thermostat) to control each of the three sources, so whilst it is possible, if it works successfully on other sources 12V/gas it's unlikely to be a thermostat problem.

 

Next thing to check, I think, would be the presence of a 230v supply to the heating element, and the resistance which should be about 350 ohm according to the info I have.

 

It would be interesting to leave the fridge on its AES setting, on hook-up with gas turned on as well, and see if it drops back to gas. This would indicate that the fridge isn't seeing 230V at the control electronics. Alternatively, switch manually to 230V mode without being hooked up, and check that it throws a fault.

 

The RMD8555 is AFAIK similar to an earlier fridge I diagnosed for a friend. The 230V supply enters the control board directly into a 12V-controlled 230V relay (switched on by the AES logic when it senses 230V is available) and directly out to the 230V heating element. On his fridge, this relay had stuck permanently on (which had some interesting effects when he was hooked up). It would be equally possible for it to have failed "off", or to be working only intermittently. It was possible on that board to cheaply replace the failed relay, but later boards may inhibit such a practice by having the components embedded in resin, inhibiting any individual replacement.

 

[rayc]

I have the same fridge and have had exactly the same problem since it was new in 2017.

On initial switch on it cools but then looses cooling and warms up. There is still heat at the top rear cover. Sometimes it works perfectly for several days, especially if it has already been cooled by gas. I have had it long enough now to have discounted levelling, AES operation or site power sources. It never switches to gas operation when in this 'failure' mode.

It works perfectly on gas, it is only when on electric. I have mentioned it to Dometic engineers who shrug their shoulders and mention control PCB.

[chris]

Robinhood and rayc Thanks . it doesnt swap over from electric to gas when on AES and no error messages come up. Rayc its good to know someone has the same problem. . Had this problem for 2 yeaars now/ think I will try a different repair shop with your info too Robinhood. Thanks

[onecal]

Hi

Have you noticed when running for a time that the front panel switch unit (between the main fridge door and freezer door) has condensation on it

Try turning on the frame heater and see will it stay working on mains power longer

Removing the switch unit under the freezer on the front and repairing the connections or replacing the card can sometimes solve this problem you outlined . . Be careful to replace the switch buttons correctly (take a photo first)

Before removing make sure all power (AC and DC) are isolated

I hope this helps point you in the right direction with this model

Regards

[chris]

Thanks onecal. We give that a look at next.