Dometic RMS 8550 Fridge

[Anseo]

I could not get this unit to work on gas.

I thought I would wait and try everything I could before posting on here for help.

I did what I could (with my limited knowledge) and followed all the advice and tips I could find on the net etc.

As pretty much a last resort, I tried a Sir Dustydog tip that he posted some time previously, this was to vacuum or blow out the area of the burner to remove spider cobwebs etc. access was very limited but I did what I could with a vacuum cleaner, absolutely delighted to say it worked.

Thank you Sir Dustydog, I have spent quite a bit of time working this problem , but very happy with the outcome ..

My opinion is that this fridge has never been run on gas other than for testing during annual servicing, no evidence of heat marks or soot etc.

I have decided to leave it running overnight on gas an give the fridge a bit of a workout on gas, is this a good idea or not?

 

[Damian]

Yes it will do it no harm to leave running on gas overnight, or as long as you like.
It is always best to use gas appliances on gas at least for a short time , say 30 minutes, every time you use the van to avoid situations such as you have already encountered and to keep gas valves in good working order.

 

[Hutch]

I think that is a very valid point Damian, I spent about 15 minutes trying to get the Fridge in my Coachman, to "Flash" up. I could hear the ignition and then it would stop, and get the fault code up, so from now on i will run it on gas for a while, every time out as I do the water heater.

 

[Anseo]

Happily the water heater and the blown air heating system fired up on gas first time I tried, the cooker I already knew was working on gas.

I am guessing, but I suspect that neither the hot water or the heating system was used on gas except for the shortest of durations.

I will now make it part of a system maintenance regime to run all gas systems for a brief time on each outing and periodically during lay-ups.

Just need to get round to installing a solar system and I will be very happy and confident when not on EHU (well at least until something fails to function hmy: )

Anseo is a Happy Haggis tonight

 

[Damian]

I think that is a very valid point Damian,"

Thanks, it is a point I have been trying to get over to caravan owners for years as lack of use on gas causes more problems and unnecessary costs when they don't work when you need them to.

I know the usual cry is " I have paid for electric so I am going to use it (to the max and more) BUT that is very short sighted and could be very costly when the electric fails and you are getting cold in your van and the fridge is thawing out all because "I have paid for electric"..

 

[Anseo]

I left the Dometic RMS 8550 on gas all night, only turning it off at 0700.

This afternoon at around 1500 I tried to light it on gas again, umpteen attempts and no joy.

Put the vacuum cleaner on top of the vent stack and around the burner area, access is so limited that the suction power applied must be very low.

Fired up on gas immediately after the vacuum treatment, I don't expect that the problem has been fully resolved.

Any ideas as to what the problem could be folks ?

 

[VicMallows]

You are giving it enough time between lighting attempts for the (unlit) gas to fully disperse? If the atmosphere around the burner is too gas-rich it will not ignite. Quite often the burner will 'pop' but not remain alight, just contributing to the problem.

A different problem is when it will not spark at all in order to ignite due to crud shorting out the spark electrode. This usually has to be cleared mechanically.

Finally, if the thermocouple (flame sensor) is failing, or (more likely) is not correctly positioned, it may not be detecting the flame and therefore although the burner lights, it will not remain on. This can also be caused by an uneven flame due to debris clogging part of the burner.

 

[Damian]

Hello Anseo,
As the last reply indicates there may be a number of reasons why you are having problems.
First is trying too many times too quickly and making the atmosphere too gas rich, or debris on the burner, or rust, or a partially blocked burner jet.
Unless you are very confident in what you would be doing to resolve the problem it is best left to a caravan engineer to service the burner and if needed replace the burner and jet.

It is very rare for the flame recognition probe to be displaced.

 

[Anseo]

Hi, VicMallows and Damien,

Points noted and appreciated, and I will take note of them.

Today, 4 attempts to light the fridge on gas were successful on first attempt.
I am a very pleased Haggis.

Dash it, but I like to know the root cause of a problem, as yet I do not know what it iswas................
OH! well, time will tell no doubt.

I really appreciate the replies I have had on here.

Thanks.

 

[Hutch]

Hi Anseo, A possibility is that you have a leak on the gas feed to the fridge, . Whats the thoughts lads.

 

[glenno]

Had a similar issue and it was the external vent. The flame exhaust is a smail separate part to the main vent on my van and this had somehow been dislodged inwards blocking the exhaust. Clipped it back where it belonged and problem solved. Had the van 4 years and first time id needed the fridge to work on gas.

 

[Damian]

Hi, VicMallows and Damien,

Points noted and appreciated, and I will take note of them.

Today, 4 attempts to light the fridge on gas were successful on first attempt.
I am a very pleased Haggis.

Dash it, but I like to know the root cause of a problem, as yet I do not know what it iswas................
OH! well, time will tell no doubt.

I really appreciate the replies I have had on here.

Thanks.

The cause was lack of use and the build up of contaminants on the burner or around the burner.
Why do caravans behave as they do,,,,,,,,because they can !!!!
They have a mindset all of their own which is totally alien to any other item on this planet !!!

 

[Anseo]

Damian,

I have now re-lit the fridge about 6 - 7 times, leaving sufficient warm up and cool down times between lighting up attempts, happy to say that the fridge now starts on gas first time every time (at least for now :woohoo: ).

As you mentioned earlier, a regular regime of using the fridge on gas seems very worthwhile, I won't forget to regularly check gas ignition on the fridge (and other appliances).

Thanks.

 

[Damian]

Glad to be of help.