Fridge does'nt cool on propane

[Rusty2867]

I recently picked up a used Dometic RM66 3 way refrigerator for my 76 Minnie Winnie.It cools down to 32 on electricity but after cooling it down I switched it to propane and it did not hold the cold.When you turn up and down the gas thermostat should the flame change? The unit is not perfectly level but is within 1/4 to 1/2 a bubble that is with a pocket level in the freezer section.Any ideas why it would work on 110v but not propane.I haven't hooked up 12v to it yet,need to find out how.Thanks,Todd

[EldoradoBill]

It most likely needs 12v to operate on propane. At least thats how my Norcold works.


Bill

[beaverman]

Yep, need that 12v to run the circuit boards on propane setting

[Aaarrghh]

Yep, need that 12v to run the circuit boards on propane setting

My 1983 Norcold doesn't use an electronic circuit board. It's likely that his, being even older, doesn't either. Mine has 12v connected, so I don't know if it will run on gas without it. My WH does (or used to).

If it it cools on AC the cooling unit is OK, so if it has a flame, it should cool. If there is a gauge in the fridge compartment that tells gas pressure, see if the pressure is what's called for on the tag on the back of the fridge. If the propane regulator is adjustable, it can be set to the correct pressure. Also try cleaning the gas nozzle. Tiny spiders can clog that.

As to whether the flame should change when the thermostat is changed, I'd like to know that, too.

At least his lights. I'd like to know why mine won't, but that's for another post 

[Rusty2867]

This fridge is out of a 79 model trailer,I don't see any circuit boards but if anyone has a diagram for hooking up the 12v it would help me.

[Aaarrghh]

If yours is anything like mine, 2 wires come from the fuse panel or from the vehicle charging circuit, and connect at the back of the fridge, like in the photo. It's that simple, but I don't know about Dometic.

At any rate, you wrote that yours does operate, and without 12v connected. 12v isn't very useful. My manual states that it's designed to just hold the fridge at whatever temp it was already cooled to. 12v is really only useful when you're driving on level terrain. It will drain your batteries fast when you're parked, and if you're driving in hilly country, your fridge should be off. Buy a bag of ice to keep it cool in that case.

[yellowrecve]

The chimney may be blocked. Is the flame a nice blue. If not there may be a blockage in the manifold. Propane pressure may be wrong (need the proper gauge for this). The jet may be partially plugged. Wash with alcohol (do not put a pin in it). The flame will reduce in size when the fridge interior reaches it's correct temp and increase to cool. There is not a large difference in size, but it can be seen.

[Rusty2867]

Thanks for the replies,I cleaned up the entire thing when I got it home including what I think is the chimney.Also put on a new roof vent and a auto changing regulator I got at a local rv store.What type of Guage do I need to check pressure? The furnace seems to kick well when I checked it the other day,I had it and a couple burners on the stove on at the same time and seemed fine.But dang it got hot in there!

[Rickf1985]

It sounds like your gas pressure is fine and as far as driving in hilly terrain it is fine, the movement keeps the liquids flowing. A 79 model should be very level to operate but that is just to keep it from burning up, it will not prevent the flame from coming on,or off pilot I should say. I doubt you need 12 volt to run it on a model that old, check what was mentioned above about clogged burners, Is your regulator on the fridge set to cool and not just pilot?

[yellowrecve]

One other thing. The thermostat for propane may not be working. On the older fridges there is a thermostat for Elect and another for gas.

[Rusty2867]

I won't get a chance to mess with it until this weekend,I'll keep ya'll posted.

[beaverman]

He stated it was a 3way

[M & J]

According to the RM66 manual it is a 3 way.

[Rusty2867]

So I took apart all of the propane system and can blow through the valve/thermostat,there is something that looks like a filter before the valve in between the shut off and the valve it's tough but I can blow through it.After the valve/thermostat is the part with the blue button that is pushed when you pull the knob to light the flame,when I push it in I can blow trough it but get nothing when I let off the button.There is a block after that not sure what it is but it is clear.I know there is an orifice in the burner and I can blow throught it but it's not easy.I know what a thermocouple does in a furnace what does it do I this case? I was going to add some pics but can't figure out how to resize them in the new windows

[Rusty2867]

pic

[M & J]

It works the same way as a furnace.

[Rusty2867]

I put the thermocouple back in the valve it connects to,held it over a torch flame and was able to blow thru the valve,I'm guessing the thermocouple is good.Know anything about this filter thing? In the pic it is in between the gas cock valve and the thermostat.

[beaverman]

Check this old page out on rv fridges  http://web.archive.org/web/20130205150849/http://www.rvmobile.com/  unfortunately the company is out of biz but there's a wealth of info archived from the old web site, may help you out!

[Rickf1985]

This sounds like it might be your issue. From that page Beaverman linked.

http://web.archive.org/web/20121013101905/http://www.rvmobile.com/Tech/Trouble/filter.htm

[Rusty2867]

I found one of those filters on ebay,$45 wow!

[Aaarrghh]

I found one of those filters on ebay,$45 wow!

I'm betting you'll gut your old filter