Dometic fridge won't stay lit

[Riverdog]

I have a 13 year old Dometic fridge.  The last couple of years the gas operation of the fridge has been a little touchy & the camper really needs to be level to work right.  I was out this past weekend, however, and now the gas won't stay lit at all.  The first day it worked ok but after that it keeps going out.

I can turn the fridge off & then back on & it lights right up -- I verify by looking to see the flame.  Then after a couple of minutes the check light comes on & I go look and sure enough the flame is gone and the fridge has shut off.

All other gas appliances work fine so I don't think its a problem with the regulator.  I had some other work done a couple of years ago & asked them to clean the back of the fridge but it doesn't look like they did a good job so I will go in and clean it out myself.  I found a thread that explained pretty well how to do a thorough job. 

I don't know if cleaning it will help much but I'll try --- although any ideas from anyone else would be welcome!

 

[TNROY]

Check to make sure the burner is clean, often times rust drops from the flue and fouls the burner. Could also be spider webs in the gas line. For some reason spiders really love gas. Another possible problem could be the thermocouple is worn out and needs to be replaced. If you could provide the make and model of your fridge it might be helpful for others trying to help.

 

[Riverdog]

Check to make sure the burner is clean, often times rust drops from the flue and fouls the burner. Could also be spider webs in the gas line. For some reason spiders really love gas. Another possible problem could be the thermocouple is worn out and needs to be replaced. If you could provide the make and model of your fridge it might be helpful for others trying to help.

Thanks - I will clean the burner, along with a thorough cleaning of the whole unit.? Correct me if I'm wrong but I don't think it can be the thermocouple.? It starts right up every time I try but dies after a couple of minutes - if the thermocouple was bad it wouldn't start at all would it?

The fridge is a Dometic - Designer Series - Model RM2607

 

[Karl]

I'm not certain, but the thermocouple may be used to detect an overheating condition, causing the burner to shut off. If this is the case, that would probably indicate a blockage in the flue.

The control boards, located near the burner, for those units are notorious for failure. Mine acted the same way. Dinosuar  http://www.dinosaurelectronics.com/ makes replacement boards for them. They don't sell directly, but you can get them thru almost any RV supply store.

 

[John From Detroit]

Thanks - I will clean the burner, along with a thorough cleaning of the whole unit.  Correct me if I'm wrong but I don't think it can be the thermocouple.  It starts right up every time I try but dies after a couple of minutes - if the thermocouple was bad it wouldn't start at all would it?

The fridge is a Dometic - Designer Series - Model RM2607

No, the thermocouple senses if the flame is flaming, The cycle is this

Gas flow starts and very shortly thereafter the control board sends voltage spikes to the sparker causing sparks which ignite the fuel/air mix  (Very Very shortly)  This remains static for a few seconds while the thermocouple heats up and sends a signal back to the control board "FLAME ON" At the point the board continues to monitor the thremocouple (in fact two temperture sensors are monitored) until one of three situtations is discovered.

1: Flame sensor thermocouple stops sending "Flame On" signal (meaning the flame went out for some reason, ie: Out of gas, Flue clogged)

2: The cold sensor (inside the 'fridge) says "Cold enough"

3: power (normally 12vdc) is lost (you turned it off, battery dead)

Thus the thermocouple in the burner area is the flame sensor, if it is not working the control board detects "Out of gas" and closes the valve for safety

 

[TNROY]

It sounds like you are at least starting out on the right track. Do the simple things first. It could possibly be a board, but you should eliminate the other possible causes first. Go to www.bryantrv.com/docs.html and you might be able to find a service manual for your fridge that you can download. At the top of his service documents is a generic service manual that might help.  Good luck.

 

[Riverdog]

It sounds like you are at least starting out on the right track. Do the simple things first. It could possibly be a board, but you should eliminate the other possible causes first. Go to www.bryantrv.com/docs.html and you might be able to find a service manual for your fridge that you can download. At the top of his service documents is a generic service manual that might help.? Good luck.

Thanks! This is an excellent link I found the manual for my exact fridge model.  This, along with the comment everyone has provided, will hopefully help me solve the problem. 

 

[Riverdog]

I think I got real lucky on this one!  I printed out the manual referred to above and found the instructions on how to clean the fridge.  It was filthy.....I pulled the burner out & dumped out at least a teaspoon of rusty dust.  This may not sound like a lot but given the burner is a tube about 3/8 in diameter and only 3 or 4 inches long, it's quite a bit.  I then blew the flue out with compressed air, removed the orifice & soaked both the orifice & burner in alcohol.  I put it back together and it lit right up.  I let it run for about 6 hours with no problems.  My only cost was the $3.50 for the alcohol.

RV repairs can be costly - it's fun to be on the receiving end of a cheap fix for once.  I also read in the manual that the burner should be cleaned once a year.  I didn't realize this but will do so now going forward. I know preventative maintenance can save large costs in the future.

Thanks to all for your suggestions.

 

[Ron]

Glad you were able to get your fridge fixed without a big expense.  Thanks for the follow up.

 

[Riverdog]

Thanks Ron -- this forum is a great resource.  It sure made the fix quick, easy, & inexpensive.

 

[TNROY]

Riverdog, I've been away for a few days, glad you found the link useful. The shop owner is a participant on other fourms and has been very helpful. Glad the manual was helpful.

 

[Riverdog]

... I think I spoke too quick on this one. I was out this weekend & the unit kept cutting out. I think you guys may be correct that it is the control board. I can "wiggle" the control board & actually make the unit click on & off....you can literally hear it click when it engages.

I didn't find any obvious loose wires so I guess the next step is to replace the control board, unless this symptom rings a bell for anyone and you have any other ideas.

 

[Jim Godward]

Pull the control board and examine the contacts, cleaned them either by using something like contact cleaner, De-OX-IT  etc OR rub lightly with a pencil eraser.

If that does not work, examine the circuit board on both sides with about a 3 power magnifying glass.  You are looking for dull solder joints and or a crack in the circuit trace.

How is you electronics soldering skills??  If good you can repair it, it not take it to someone who is skilled and see if this solves the problem.

 

[Riverdog]

Thanks Jim -- I'll give it a try.  If I do find a suspect solder I do have a friend who's pretty good a soldering.

 

[Karl]

Jim,

Most all of those boards are potted, and he won't be able to check for cracked/burned traces.

Riverdog,

Jim's suggestion to clean the contacts with an eraser is a good one. If you can still hear it clicking after that, get a new one - around $100. Then you won't have a fridge full of yuckey green, moldy something. Most RV dealers with repair facilities can test your old board.

 

[Riverdog]

Thanks Karl.  I have priced the boards & can find them for the price you discussed.

I talked to a couple of RV dealers & one dealer told me he could test it, but wants a minimum $50 shop fee.  At that rate I'm half way to a new board so would be inclined just to spend the extra 50 & get a board that has a warranty.  The other dealer I talked to said they would be happy to test it but have found that it's pretty common for it to test out as "ok" only to find out the board is really bad.

I think I'll clean the contacts like both of you suggested & if that doesn't do it then just get a new board.

I didn't have any yucky green stuff this weekend but I did end up with warm beer & pop along with a little ice cream pudding.  mmmmmmmm

 

[Gary RV_Wizard]

If you need a replacement board, the Dinosaur brand comes highly recommended. They have made a reputation for themselves with high quality, rugged replacements that equal or exceed anything from the OEM.

 

[Riverdog]

Thanks - I found their boards in my search.  They seem to be the best priced & they also give a 3 year warranty.  For the board I need (a P-711) I'm finding the price right at $100.  One of the distributors even ships for free.

 

[Riverdog]

I received my new Dinosaur board on Monday & installed it right away. I ran it Mon night & Tue am on AC & it worked perfect followed by running it Tue afternoon & night on gas - also worked perfect. Looks like the problem is solved. Thanks for the comments everyone!

 

[Ron]

Glad to hear you got it fixed. Thanks for the follow up.  Nice when a plan come together. ;D