Dometic RMDT8505 fridge freezer - not cooling on Mains Electric

Abacist

LIFE MEMBER
Oct 15, 2013
2,520
4,016
Devon
Funster No
28,581
MH
A Class
Exp
since 2013
This works fine on both gas and 12 volts but is not working on 240 mains voltage, or if it is, it is not noticeably performing any cooling or freezing function.

The unit does not display any of the handbook error lights or beeps but seems happy to apparently operate on the mains button.

The history of the vehicle is that we bought it in August 2018 after little use by the 2 previous registered keepers and shortly thereafter the mains side stopped working. When in Germany visiting the N + B factory they arranged for a Dometic engineer to service the fridge/freezer and he replaced both mains heating elements. The fridge/freezer then worked for some time but stopped working again when we came to use it in 2019. Since then we have either been in lockdown or have used it on 12 volts or gas only.

I have today checked it over again. It is definitely running on mains but not producing any error flashing lights or beeps but is certainly not cooling or freezing.

We would like to get it fixed but 2 dealers have now turned us down for either not feeling capable or are too busy. I have just sent an enquiry to another Dometic Service agent.

I am wondering if anyone on here has any ide what might be wrong.
 
Oct 29, 2009
2,897
5,304
Derby
Funster No
9,111
MH
Dethleffs
Exp
Since 2006
If it cools on the two other power sources then either the a.c. heating element(s?) have failed or they are not being provided with a.c. power.

Are you able/competent to use a meter to check for 240V at the heating element terminal block?

Ian
 
OP
Abacist

Abacist

LIFE MEMBER
Oct 15, 2013
2,520
4,016
Devon
Funster No
28,581
MH
A Class
Exp
since 2013
If it cools on the two other power sources then either the a.c. heating element(s?) have failed or they are not being provided with a.c. power.

Are you able/competent to use a meter to check for 240V at the heating element terminal block?

Ian
Hi Ian
Having read the Dometic manual for the fridge it is supposed to have flashing lights and beeps if the elements have failed which it is not doing so I wondered if it could be something else, especially as the heating elements have not long been changed. The german guy who changed the elements did it with his hands up the back of the fridge, blind, through the bottom vent. I have looked with a mirror and am having trouble seeing where the ends of the elements are!

Subscribers  do not see these advertisements

 
Oct 29, 2009
2,897
5,304
Derby
Funster No
9,111
MH
Dethleffs
Exp
Since 2006
I would expect the elements to be terminated in, unsurprisingly, a terminal block that ought to be accessible behind the lower fridge vent. The elements may not have failed it may simply be that something else has failed. Establishing whether or not a supply is present at the element/terminal block will help diagnose the problem.

However, if you are unfamiliar with electrics perhaps it‘s best to leave investigation to someone better qualified.

Ian
 
OP
Abacist

Abacist

LIFE MEMBER
Oct 15, 2013
2,520
4,016
Devon
Funster No
28,581
MH
A Class
Exp
since 2013
I would expect the elements to be terminated in, unsurprisingly, a terminal block that ought to be accessible behind the lower fridge vent. The elements may not have failed it may simply be that something else has failed. Establishing whether or not a supply is present at the element/terminal block will help diagnose the problem.

However, if you are unfamiliar with electrics perhaps it‘s best to leave investigation to someone better qualified.

Ian
OK I will check for power behind the fridge.
 

Lenny HB

LIFE MEMBER
Oct 18, 2007
30,037
52,368
On the coast in West Sussex
Funster No
658
MH
Hymer B678 Dynamic Line
Exp
Since 2008 & many years tugging
Must have been fixed by a top quality engineer, how did he manage to change 2 elements the 8505 only has one.

If its not the element its most lightly the black unit on the back of the fridge it controls the power switching & gas ignition. Common fault on the 8505 not cheap around £200 not repairable as all the electronics inside are potted.

peterc10 had the same problem.
 
OP
Abacist

Abacist

LIFE MEMBER
Oct 15, 2013
2,520
4,016
Devon
Funster No
28,581
MH
A Class
Exp
since 2013
Must have been fixed by a top quality engineer, how did he manage to change 2 elements the 8505 only has one.

If its not the element its most lightly the black unit on the back of the fridge it controls the power switching & gas ignition. Common fault on the 8505 not cheap around £200 not repairable as all the electronics inside are potted.

peterc10 had the same problem.
Thanks Lenny

Subscribers  do not see these advertisements

 
Jul 5, 2013
9,662
9,900
Tunbridge Wells
Funster No
26,797
MH
A class
Exp
Since 2013
Must have been fixed by a top quality engineer, how did he manage to change 2 elements the 8505 only has one.

If its not the element its most lightly the black unit on the back of the fridge it controls the power switching & gas ignition. Common fault on the 8505 not cheap around £200 not repairable as all the electronics inside are potted.

peterc10 had the same problem.
With my problem the warning lights were flashing, which the Domestic manual suggested was a failed 240v element. Eventually found one with the help of Lenny HB but decided to get it fitted at a dealer. Turned out my dealer (Becks, now sadly closed) knew more about the fridge than Dometic did and quickly diagnosed that the black block had failed, simply by testing the output from it, or lack of it. This was such a common fault that they had one in stock.

£200 later it was fixed. The good news is that if it is the element on yours I have one I can sell you :LOL:
 

sallylillian

LIFE MEMBER
Oct 29, 2011
3,697
4,443
Falmouth, Cornwall
Funster No
18,670
MH
Palace Liner 90LO
Exp
2011
I had a 230vac element failure on my 8 series on the Flair. No warning light, no nothing, just not cooling on 230vac. It was in warranty and we were in Portugal. I called local Dometic agent and mobile engineer came, he had zillions of different powered elements to cover the panoply of options Dometic produce. He checked the 230vac in to the fridge and at the element wire connections to prove continuity then the resistance across the element +ve and -ve and declared the element dead. He replaced it under warranty save for the call out charge of €25.
 
OP
Abacist

Abacist

LIFE MEMBER
Oct 15, 2013
2,520
4,016
Devon
Funster No
28,581
MH
A Class
Exp
since 2013
Right I've checked that there is AC voltage going into the black box but having trouble checking if there is anything coming out as I've not worked out how to get the white connector off that takes the power up to the element but its progress!

Also I had left it on overnight on EHU and it was in error mode this morning with red light flashing next to the on/off blue light and also the triangle with the exclamation mark.

I am trying Caradoc in Ivybridge who are supposed to be Dometic Service Approved.

Subscribers  do not see these advertisements

 
Oct 14, 2020
18
3
Funster No
76,904
MH
Dont own one yet
Exp
I'm a newbie
I have same issue with my dometic RMD 8505 , no cooling on EHU or 12v with engine running . Lights on the panel are showing its cooling but in effect the fridge internal is ambient - I did once have the red flashing triangle fault light but not seen it for a while now.

Spoke to a local mobile eng, he's hoping to get element and electrical boxes one sale or return basis and check it out / replace as necessary ...

I did wonder if I should replace the heat sink paste at same time ..
 
Top