Dometic AES fridge switching to gas on hookup

[Vouty]

Hi Folks,

We have recently bought an oldish Hymer van (1997) with a Dometic AES fridge.

It seems that when we are on hookup, every now and then the Fridge will intermittently try to switch over to gas. Doesn't seem to be any rhyme nor reason to it, could be fine for a few hours and suddenly decide to do it.

I'm planning to get someone in to take a look (and hopefully fix under insurance based warranty) but just wondered if anybody had any thoughts as to what the problem might be. Have tried both on our drive and at a campsite so don't think its a supply voltage issue.

Cheers

Carl

 

[jezport]

1 Check your hook up supply is working correctly.
2 Check your hook up lead and socket on the van
3, Check that the mains connections at the back of the fridge are not loose.

Poor mains supply can cause this, I have had it at one meet where hook ups were split many times.

 

[makems]

I was going to suggest supply voltage but it looks as though you've ruled that out.
I have had a problem with the fridge switching to gas when the voltage is out of whack in Morocco on a few sites which I have sort of resolved by using a voltage stabiliser that I bought in Morocco.
The strange thing is the fridge was brand new, and I didn't have the same problem on the same sites the previous year in our previous van which had an older fridge!

Strange things these fridges....

 

[johnp10]

We have an AES fridge/freezer.
Every now and then it goes through its search cycle for power and gas.
It stays on mains though, doesn't actually switch, mains taking precedence.
I asked an engineer about this when he fitted a new board.
He says it's normal on the older AES fridges.
(Our van is 2000)

 

[Vouty]

Hi John,

does this involve a 'clunk'noise that sounds like the gas isolation valve?

Problem with this generation of AES fridge is there is no indication of which power source it is using.

If its meant to operate like that then fair enough, however it can be a bit disconcerting when it does it in the middle of the night. I guess we could sleep with the fridge off - I like stuff with manual controls for turning off and on, at least I know where I am with them!

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[DavidG58]

Is it fully auto? ie can you not set it to mains electricity rather than AES?

 

[johnp10]

Hi John,

does this involve a 'clunk'noise that sounds like the gas isolation valve?

Problem with this generation of AES fridge is there is no indication of which power source it is using.

If its meant to operate like that then fair enough, however it can be a bit disconcerting when it does it in the middle of the night. I guess we could sleep with the fridge off - I like stuff with manual controls for turning off and on, at least I know where I am with them!

Clunk...Yes.
You get used to it.

Is it fully auto? ie can you not set it to mains electricity rather than AES?

Fully auto, just switch on and it does its AES thing.

Switch the gas supply to the fridge off, May stay on EHU.
There is a fault if it chooses gas with an electric source available?

 

[Vouty]

No I'm afraid not, in their wisdom the designers thought it best that the fridge make all the choices and the user should not worry their little head about which power supply it is working from. All well and good when things are working fine.....

I 've been very suspicious of automatic mechanisms that aren't really required, ever since I had similar issues with the electronic parking brake on a VW Passat. Once ended up with a queue 1/2 a mile long behind me when the b**dy thing refused to release at traffic light.

Funny thing is we are pretty light users of electricity when camping so don't expect to be on hookup that often, even less if I install a solar panel.

 

[Vouty]

Switch the gas supply to the fridge off, May stay on EHU.
There is a fault if it chooses gas with an electric source available?

Will try this, if I haven't already. Just need to be sure there isn't a fault - I ought to download the manual for my particular model. The Hymer manual I have doesn't really have any useful info other than switch on and enjoy.

 

[Sundowners]

Hi John,------- - I like stuff with manual controls for turning off and on, at least I know where I am with them!

That's why we replaced our erratic AES fridge with a manual selection one------
Anyone want an AES erratic fridge ??????

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[johnp10]

Dont find ours erratic.
Quite efficient.
On leaving a site and disconnecting EHU or gas, it fires up on 12v automatically as soon as I start the engine.
Easy thing to forget.
The cycle search is something or nothing.

 

[DavidG58]

Fully auto, just switch on and it does its AES thing.

Switch the gas supply to the fridge off, May stay on EHU.
There is a fault if it chooses gas with an electric source available?

I agree, that is what our newer AES does, but we can also turn control to one source rather than AES, that I thought might stop it playing silly buggers with itself maybe

still needs looking at but might remove some of the clunking concerns until fixed

 

[technical-phil]

Hi Carl,
Sounds like you have a 6-series fridge, also known as an AES2
Two buttons on the control panel, one for on/off, one to 'dial' temperature?
Random selection of gas after running on 240v for 10, 20 mins, or intermittent switching is usually caused by one of two faults, occasionally both:
If you take the bottom ventilation grill off, behind the fridge on the outside, you will possibly find a 'continental' two pin mains plug & socket on the left hand side.
This is the 240v supply to the fridge. Pull the plug & check for corrosion on the pins, it is open to the elements & a bad connection can make the fridge think that 240v has failed.
Just pulling the plug out, then plugging it in again can occasionally cure the fault.
If there is no plug/socket then the 240v supply is probably 'hard wired' (a much better option!) & will rule this out.
If the 240v supply is sound, then you probably have a faulty control board, as the symptoms you describe indicate.
There will be a characteristic scorch mark on the surface of the PCB which shows this is the case.
The original board was upgraded about a year or so after this model range was released.
Upgrading to the newer version has always cured this fault in my experience.
Hope this helps!

 

[JockandRita]

I know this thread is almost 4 x years old now, but we appear to have the same problem as the OP, so for now, we have isolated the gas supply, and waiting to see if that has any effect.

I am reliably informed that parts for these older Electrolux AES units are now obsolete. Ours is the RM 4505 AES II model.
In the event of not finding an exchange PCB, does anyone know of a source that can repair the existing PCB please?

Cheers,

Jock.

Edit..............The unit went through it's search cycle for power, showed a flashing red light, (no gas) then a steady red light (failure), then back to green again (working correctly) when it chose 240v, so that will do as a temporary measure for now.

 

[rb62]

I know this thread is almost 4 x years old now, but we appear to have the same problem as the OP, so for now, we have isolated the gas supply, and waiting to see if that has any effect.

I am reliably informed that parts for these older Electrolux AES units are now obsolete. Ours is the RM 4505 AES II model.
In the event of not finding an exchange PCB, does anyone know of a source that can repair the existing PCB please?

Cheers,

Jock.

Edit..............The unit went through it's search cycle for power, showed a flashing red light, (no gas) then a steady red light (failure), then back to green again (working correctly) when it chose 240v, so that will do as a temporary measure for now.

There are some control units available on e bay,about £250 once you've worked out which one you need .How reliable they are I don't know.
http://www.apuljackengineering.co.uk/ also say they do Dometic AES so might be worth a call.
We just never use the AES function!

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[jezport]

Jock,
I had this in our Frankia, it was a dodgy mains supply. Can you plug the van in a different socket? If that doesn't work, try another EHU lead. And finally remove the rear grill on the fridge and run a mains lead directly from the fridge to a mains socket at home.
Then you need to see if there is a mains smoothing capacitor across the mains supply (part of the fridge) and fit a new one as they are cheap and worth a try.

 

[JockandRita]

There are some control units available on e bay,about £250 once you've worked out which one you need .How reliable they are I don't know.
http://www.apuljackengineering.co.uk/ also say they do Dometic AES so might be worth a call.
We just never use the AES function!

Thanks, I'll contact Apuljack Engineering, whom I had forgotten about.

Jock,
I had this in our Frankia, it was a dodgy mains supply. Can you plug the van in a different socket? If that doesn't work, try another EHU lead. And finally remove the rear grill on the fridge and run a mains lead directly from the fridge to a mains socket at home.
Then you need to see if there is a mains smoothing capacitor across the mains supply (part of the fridge) and fit a new one as they are cheap and worth a try.

Thanks Jez. Our unit is hard wiedw .into a junction box, and at three different sources, the same problem exists. That at least tells me it isn't a mains voltage drop which is causing the issue. Since isolating the gas supply, the unit hasn't faulted, so again, confirming good voltage.

Cheers,

Jock.