Dometic fridge won't switch off

[Colin17]

Dometic RMS 8551 fridge 2013 vintage in a Knaus Van Ti, working on all 3 power sources, it is manual selection.
For a long time there has been an issue with switching the fridge off. Pressing the button switches off but within a few seconds it restarts.
The other day I noticed the fridge alarm going off although it had not been used for about 3 weeks. Somehow it had switched itself on, and I was unable to switch it off as above it kept restarting.
I took the switch panel out and fiddled with the switch. Although there was nothing obviously wrong on reassembly it was possible to switch off.
All OK for a few days then the same thing happened again except I could not get to switch off. I disabled by pulling the fuse and left for a couple of days. I have just tried it again and have switched it off OK.
I can't find this problem mentioned here. Looking for suggestions on what to try. Should I be expecting to replace the panel?

[colin]

As a temporary solution, will switching off the main control panel for van disable it? 

[onecal]

Hi

Isolate the supply as advised, first

Dry out the panel with moderate heat (hairdryer) and see it it works then after operating the switches (buttons)a few times

Regards

[Colin17]

5 hours ago, colin said:

As a temporary solution, will switching off the main control panel for van disable it? 

The fridge control is on a permanent feed, which is why I pulled the fuse.

[Colin17]

4 hours ago, onecal said:

Hi

Isolate the supply as advised, first

Dry out the panel with moderate heat (hairdryer) and see it it works then after operating the switches (buttons)a few times

Regards

Thanks I'll try the hairdryer.

[Globebuster1]

Whilst it may well be the control panel, I think to could be a precursor to the sealed control box on the rear of the fridge failing.

That's been my experience, and that of may others it seems.

[Colin17]

Update: I did the hairdryer and 3 days on it has not restarted itself. Switches on and off. Looks good so far.

[onecal]

Hi

Glad we were all able to help, Moisture can be a major issue, 

Regards 

[Colin17]

Update: 3 weeks on including a few days away and we have had no further problems, fridge worked perfectly while we were away. 

Drying out seems to have done the trick. Thanks for the advice.

[artful]

On 31/01/2023 at 12:04, Colin17 said:

Update: 3 weeks on including a few days away and we have had no further problems, fridge worked perfectly while we were away. 

Drying out seems to have done the trick. Thanks for the advice.

I found this forum thread via a Google search as I've just experienced the same problem after returning from a two week tour in the caravan. Our normal practice is to switch of the RMD8551 and empty it then leave the doors cracked open overnight then cleaning and drying it out the following day. On going in the following morning it was on and the blue warning LCD was flashing which has never happened before. I switched it off but it restarted almost immediately. I eventually pulled the fuse, cleaned and dried it out and searched the web for information.

On finding this thread I removed the control panel which had droplets of condensation on the inside face and dried it out. On reassembly it seemed to work in all 3 modes but continued to restart after switching off. However, I found that if I closed the door immediately after switching off it stayed off.

My Bailey Unicorn Barcelona is a 2015 model which we're very happy with it but I did have to replace the control panel in January 2019 after it stopped working. Interestingly that was after 38 months of use so this control panel has developed a fault after around 41 months although not a complete failure. I haven't contacted the dealer as they'll probably just tell me to replace the panel and the current price appears to be over £300 which I'm not happy about.

I don't know if this is a common problem but at the moment we're due to go away again in a couple of weeks so I'm going to see how it goes. I took the van back to store so pulled the fuse just in case it decided to restart itself again and I did shut the doors this time where I normally leave them cracked open.

The control panel does not have a waterproof seal to the frame so it seems it's susceptible to moisture ingress so I suspect this may be a common problem but I couldn't find much evidence of that from a search on the web.

I'd be interested to learn if yours and / or others are still problem free as this is a potential headache.

Doing a bit of research it seems that the current replacement for this unit is the Dometic RMD 10.5XT which costs around £2600 but the Thetford N4175 is a viable replacement at around £1600. The Thetford appears every bit as good from the information I've found so if I had to replace the RMD8551 I think I'd go for the Thetford.

[onecal]

Hi , 

I really think you may have answered your own question with the door So use your frame heater No 6 on attachment photo before shutting down and and again when in use when needed to prevent condensation droplets forming . Check your door seal it may not be sealing properly Replacement of the seal maybe necessary to prevent as you say further potential headaches, Replacement Control panels are available , even updated ones from third parties but always try to solve the initial cause first to prevent further failures of same.   I hope you found our forum helpful . 

Regards

[Labby]

 artful , It may be worth talking to www.apuljackelectronics.co.uk about your problem as they now do their own replacement control pcb for some Dometic 8 series  fridges , as shown in their website catalogue .

[artful]

Thankyou both for your helpful comments and I'll check out apuljackelectronics. I must admit I've never used the frame heater but will try that. It appears from the manual that it switches off automatically after a couple of hours and I'll check the door seals, particularly the freezer compartment.

[onecal]

Hi,

Yes you need to use the  frame heating (12VDC/3,5W)  During summer months with high temperatures and humidity the metal frame may have water droplets forming. To evaporate these droplets switch on the frame heating with button (6) as per photo.The operating time of the frame heater can be set to 2 hours, 5 hours or continuous operation. After selecting the operating time using the button (6), the temperature level indicator (8) is extinguished for a short time to show the set operating time for a few seconds. The display then returns to the temperature level indicator. You always need to solve the issue before replacing the control panel, Check the door seals (both) carefully for damage, (when the door is closed , they (seals) should be able to grip a sheet of paper all around) Also do a check around your fridge that there is no draughts from the rear to the inside of the motorhome along the sides of the fridge and correct poor installation if found.

Regards