Dometic fridge RM 2553 problem

"Thermostat problem? very likely, especially if has been heavily used on 12v." RM2553 on 12v does not function on the thermostat. 12v is direct connection to 12v element.

240V elements are crap. On 12v your wiring is probably to light.

I can't speak for certain on Dometic, but Chescold 3 way fridges have only one element that draws 175 watts on either 12 or 240. I'd be surprised if Dometic found a need to install two elements where one would do the job. But I'm only guessing.

Jim.

The 12 and 240 V elements are two separate devices. The common device seems to be to be the thermostat - as reported by oldtrack.

PeterD

Jim, there is no thermostat on the SEPARATE 12v element, only on gas and electric does the thermostat operate.

Our Dometic is fussy about levels, seems to work best when the front of the van is a little lower. Perhaps a quirk of installation but generally, must be level.

Check the element, on 240v it will be hot to touch. Easy to see through the bottom vent, (assuming normal installation). Gas heat can be similarly felt at the flue exit in the top vent. If these indications are good, feel the topmost pipe of the condenser, should be getting hot too. If not, you need a fridge mech.

All the best,

Hi All
Just to confuse everyone a little more here are some FACTs on Dometic 3ways

Some of the larger models do only have one 240v element which is ran by a crude inbuilt inverter from 12v supply

MOST have separate12v & 240v elements

Very old models did not have the thermostat operate when on 12v
For the last 15 to 20 years many models have had thermostatic control on 12v
Some of the later larger ones now have a relay on the 12v element feed to take the load of the thermostat contacts

Model & serial numbers are important in finding just what you do have

I still believe that the thermostat is the OP's problem

I do agree that the later model s 240v element are not lasting & would advise anyone who finds this happening to not be put off by dometic blaming voltage surges & suggesting surge protectors.
These will not solve the problem
The elements are running hotter than they should because they have not been designed for our standard voltage

Peter

Excellent advice and much appreciated.
I do have a multimeter. Used it to check if the power was getting to the fridge.
Question; the thermostat doesn't control the fridge on gas only on power?

Hi Magillas

The much perpetuated story that dometic 3ways do not have thermostatic control on 12v is WRONG
A BIT LIKE AN Old WIVES TALE WHICH KEEPS GETTING REPEATED
Many models do ,some do not.
I cannot be sure with your model but the manual should indicate if it does
Also the circuit drawing on the back should also indicate
Another way is if the manual tells you to turn the thermostat knob from "off" to a number
If the elements test ok the only other common feature to both is the selector switch, but it is very unlikely to be the problem ,as it is a multi pole switch & uses different contacts to feed the 240 & 12v

The thermostat IS a gas /electric one.
It has electrical contacts which could be the problem as the one set is used to control both the 240v & the 12v elements ,& which will not affect the gas operation

Peter

Hi Magillas

A bit of quick research seems to indicate your model HAS THERMO CONTROL ON 12V , but not directly. it controls a relay to take the load of the thermo contacts as I posted above
I still believe the thermo is the most likely problem , the other possibility is wiring ,especially to & from the thermostat, from the selector switch
Peter