Proper use of Dometic Fridge

B_Rubble

Dear Anybody,
I have a 3way dometic fridge (RM4200). It works beautifully. Here is the newbie question.
When I leave the van for the day in a spot that doesnt have 230V do i leave it running on gas or run it off 12V. The latter seems to be less dangerous but may run my battery down. Experiences gratefully appreciated.
many thanks in advance.
B_Rubble

stapeler

A similiar subject was discussed last week. When parked up gas is required as the battery will not last very long without the engine running, the fridge typically runs at about 100watts. Most are configured so that when the engine is running the fridge automatically switches to 12V dc.

peasant

If your van is configured and wired properly it simply won't run on battery once the engine is off, no matter what you set the switch to.

This is designed that way to save the battery.

peasant

The most economic way to use your fridge is to cool it right down on 230v during the night before you take off. Then fill it, run it on the highest setting on battery while driving and then when you're parked, about half power on gas will keep everything nice and cool.

Full power on gas may actually freeze your stuff, especially with irish outside temps. Full power is only necessary when it's really hot outside.

B_Rubble

Many thanks for that advice. I'll feel a little safer leaving the gas on.

dollydishmop

peasant wrote:

Full power on gas may actually freeze your stuff, especially with irish outside temps. Full power is only necessary when it's really hot outside.

Seconded! *LOL* We often find our milk frozen solid even on the hottest days, at only half setting on gas

Terrontress

I am having difficulty with my fridge. It seems to be an all in one unit with the rings above. As the rings above are working there seems to be no issue with gas getting in.

I have tried turning the switch on on the fridge and clicking the ignitor but am having no luck.

The fridge is an Electrolux and is most likely 25 years old.

Does anyone know how I could tell if it has lit or if there is any start of stopcock or the like that would prevent it from working?

I'd love to get it going.

peasant

I doubt that it is an all-in-one design ...would be the first one I've ever heard off. (the hob isn't very deep and just sits on top of the fridge)

Older fridges used to have a little looking glass (usually bottom left corner on the inside) so that you could see the flame burning,
After a few years of muck and soot you'll only see it when it's dark, if at all.

A properly plumbed in gas installation should have a separate stop cock for every appliance, go rooting for the one for the fridge and set it the same way as the cooker.

Is the ignitor actually klicking, if so is it automatic and continuous or is it a manual one?

Usually you also have to hold down another button when igniting an older fridge. It's either the one where you select the temperature or another, smaller (usually red/brown) one that you have to keep pressed while igniting.
Set the temp on full, hold the button down for a while to let some gas stream in, then ignite (and try again:D ). You should hear a bit of a "whoosh" sound as the gas ignites followed by an ever so faint roar as the flame burns.

Another way to find out if your gas is burning is to take a look at the exhaust. If warm air is coming out of that one (smelling of burned gas) you were successful.

Also make sure not to have your fridge running on 12V / 230v at the same time.

Terrontress

As ever, thanks Peasant. I will take a look later. I wasn't holding down the button. I found the stop cocks and I have the fridge one set to the same as the hob one, which I know is on, so I don't think it is that.

It's a manual ignitor. The sort where you push in a spring loaded button. I am not sure if it is sparking at the other side.

The van had a gas test carried out by Tuev last year and passed it all so I am expecting it to work properly.

peasant

A manual igintion is actually a good thing ...they hardly ever fail. It's a manual piezo thingy, so pretty indestructable and no electrics to stop working.

When holding down the gas button (or the extra button) just wait a bit ...it takes time for the gas to reach the burner.

If you can't find a gas button that pushes in, sometimes the buttons get stuck ...take the plastik knob off and see if the metal pin underneath is pushable.

You might have to put something into the knob where the pin fits, so that the knob sticks out more and can actually be pushed in ...they wear out sometimes.

peasant

Terrontress wrote:

Peasant, your genius knows no limits!

It is definitely burning. Was able to find the little window to the flue that you spoke about and got it lit after many attempts. I've left it running and am going to go back out in 20 minutes and see if it does a cooling job. With any luck!

MOD EDIT
second half of post moved to new "water damage" thread

loobylou

Hi Peasant,
Frohes neues Jahr, I have similar problem to above, I've cleaned the little window in the corner of the fridge and am not getting any spark. Gas is switched on and fridge works fine on 230v and 12v. Does the ignitor need replacing and how would you do this?

peasant

Depending on the age and type of your fridge, for the older fridges there are threee models of igniters.

1) manual
You press the button (like a piezo ignition on a lighter, just larger) and one spark travels down some wires to the burner. Always works unless the ignitor is really and truly broken

2) battery powered
you press the button, the ignition goes "tick, tick tick", power comes from a separate little battery hidden somwhere around the fridge (usually at the bottom, behind a panel and difficult to find). Spent battery ...no ignition

3) vehicle battery powered
same as above, only the ignitor is wired into your vehicle electrics.
All sorts of possible failures ...insuficient battery voltage, bad contact, bad earth, broken wire.
The fun is in finding where everything is and then checking it.


Is there any way you can get at the back of your fridge to check the burner?
Maybe take off a vent ?

Diagnosis is so much easier when you can actually see what's happening at the business end.

Is there a spark at all? Does the spark connect with the gas to create a flame or is it sparking uselessly off something else? Can the flame burn freely or is the burner obstructed and the flame just dies? Does the burning flame actually heat up the the cooling circuit or is it blocked/diverted and just burns without effect?


So many different things that can prevent a gas fridge from working properly ...hard to diagnose over the internet.

loobylou

Its the manual piezo type, I can't see any spark thru the small window in the fridge. I took off the vent which gives some access to the business end of things but cannot see anything obviously wrong. As I'm on my own at the moment I can't see from outside whether its sparking or not, I'll try later when its dark and I have someone to help. I presume the spark (if present) can be seen from the outside once the vent is removed??
Ian

peasant

You can't see the spark through that little window ...you're lucky to see the flame.

and yes, you should see the spark from the outside, especially at night.

dollydishmop

peasant wrote: »

You can't see the spark through that little window ...you're lucky to see the flame.

Well...you can clearly see both the spark and the flame through the small windown in my 3-way Dometic fridge....and its an ancient fridge....at least 15-20 yrs old.
After all...that's what the window is there for! You have to have your head at the right angle though, but once you know where to have your head and where to look for the spark/flame you're laughing.

I find mine can be a total pain to light on 12v if it hasn't been used for a good while. With mine you just have to be patient and keep trying.
Once you've got it lit (and left it running on gas for at least an hour or so) it'll relight easily the next day etc.
Sometimes it helps to turn the gas *down* a little, as if its flowing too strongly it will sometimes blow itself out just as it ignites...if you know what I mean.
Once I can get it going *poof* (i.e. gas and spark meeting in a joyous union) but not holding the flame, then I turn the gas down slightly and then it lights fine, and doesn't *woof* itslef out just as it ignites.

*Kol*

Dont forget that you have to keep the gas knob pushed in for about 15 seconds after the flame lights in order for the flame to keep going. This activates an anti flame out mechanism in the fridge (same for heaters). If you release the knob before the 15 secs the flame will go out.

loobylou

Tried again in the dark with vent off and am definitely getting a spark. The gas however is not igniting. Fridge is level, have held the gas flow button down for 20-30 seconds, etc. Did notice when the vent was off that there was a smell of gas (not strong) so it would appear to be getting through, perhaps theres a partial blockage in the pipe. If it was airlocked would there be any smell of gas at all?

peasant

loobylou

as it seems to be easy enough to get at the back of your fridge, I would recommend the following:

Get yourself a brush and clean the whole burner area of dust, dirt and debris. If it still doesn't work then, take it to a plumber who knows about gas. Might just need some minor fiddling ...might need new parts.

But you don't really want to mess with gas and get it wrong.