Dometic Fridge Issue

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shelad06

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Good morning everyone. I'm new to both the site and the whole RV thing. I have a 1994 Tioga w/ a Dometic RM2611 fridge. The fridge works good on both gas and AC but the igniter works intermittently. Usually I need to light the burner manually. I checked wires, fuses(i could find). Since it does work at times, I am thinking connection. Any ideas? Any help would be appreciated. Thanks.
 
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John From Detroit

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I have not seen this with a fridge but I have with two furnaces (out of 3 I have worked on the 3rd was NOT DSI) the spark gap. Measure it, then go to the fine manual and see what it is supposed to be... Only Guarantee I give however is the ultimate money back. Your Free is already refunded.
 

shelad06

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Yuma Az
So I think I may have been a bit hasty claiming problem was solved. About an hour later, the fridge wouldn't fire up on propane. But yesterday, I was going to dig into it again, and I tried to fire it up first and it worked great. After I shut it down, after a waiting a while, no fire. Now I looked at the thermister, and the tip has been cut off. Would that cause thus type of problem? Thanks Larry
 

Henry J Fate

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There should be a thermistor (tip) on the cable inside the cabinet. The tip is the thermostat that sends the signal to the board for cooling/no cooling. I would get that resolved. There are kits that put a new tip on existing cables and are a lot cheaper than replacing the entire cable. Google is your friend.

Thermistors decrease resistance as the temperature decreases. Thermistors will increase resistance as the temperature increases. The control board takes that information and responds accordingly. It is possible that your fridge is not cycling and is on full time not having the tip on the end of the cable.

The burner problem appears to be something unrelated to the thermistor in the cabinet but to be sure, verify that the burner is trying to light but is failing to produce a flame. In other words... If the fridge is calling for cooling and the control board is sending the signal to the burner to ignite but no flame is present, then you probably have a burner problem. This can be determined by the gas valve opening creating a smell of raw gas, sparking from the electrode but no flame produced, sparking and a flame then a quick shut down or possibly some intermittency of either.

The electrode is also a flame sensor. It should be mounted properly in the burner in order to ignite the gas in the start mode but once a flame is present, the electrode sends a signal to the control board that all is ok and a flame is present. If flame detection does not occur during start up, the control board will shut the flow of gas off and end the start process. There may be some variation in the sequence during and after but that should help you troubleshoot. If the electrode/sensor is adjusted properly and is not performing both functions, replacing it would be the first step and fairly cheap.
 

shelad06

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Yuma Az
When I press the on button, I get the auto light. A second or two later I hear a click and the gas light comes on. After that one of two things happen. Either the unit lights, or it goes sends gas to the burner for 20-30 seconds and then shuts down. This is when the check light comes on. During this 20-30 seconds, the is no spark from the igniter. I can smell the gas, so I'm thinking that part is ok. Just no spark at times. I did order the repair kit for the thermistor, plus I had ordered a thermocouple. Is there a way of testing the igniter, or the control box? There isn't really anything else.
 

Henry J Fate

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No sensible way of testing the ignitor/sensor at the burner. Just replace it should be less than $25 or about. Make sure it is adjusted properly to the burner. This is important to assure a spark can be attained. Usually between 3/32 and 1/8 is specified but you will need to look that up for the 2611. Make sure the connecter for the ignitor/sensor is clean at the control board. Carefully pull it off and clean any rust off the connector and plug it back in.

Also make sure that the electrode/sensor is not only gapped properly but is sitting in the flame once a flame is present. This will enable the electrode/sensor to send the flame verification to the board however it seems it is performing that function if when the gas has ignited it stays lit. If the flame appears then the burner shuts down, the board is probably not getting a flame confirmation.
 
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Kirk

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When I press the on button, I get the auto light. A second or two later I hear a click and the gas light comes on. After that one of two things happen. Either the unit lights, or it goes sends gas to the burner for 20-30 seconds and then shuts down. This is when the check light comes on.
That is exactly what is supposed to happen.
Is there a way of testing the igniter, or the control box?
There is but it is expensive and many RV techs do not own one, but most authorized repair shops do have one. Some of them will test a circuit board for a customer but most charge a fee to do so. As Gary has said, it if far more probable that the problem is the ignitor as the circuit boards rarely fail.
 

shelad06

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Yuma Az
That is exactly what is supposed to happen.

There is but it is expensive and many RV techs do not own one, but most authorized repair shops do have one. Some of them will test a circuit board for a customer but most charge a fee to do so. As Gary has said, it if far more probable that the problem is the ignitor as the circuit boards rarely fail.
Ok. I went through and checked every connection. Cleaned every ground. And if I manually like the flame it stays going until I shut it down. Just no spark. Well, sometimes. So I'll order an igniter. Just kind of strange how it will work sometimes and not others.
 
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Henry J Fate

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The electrode/sensor relies on the burner tube for a spark. If the burner tube is rusted in the area of the electrode/sensor, it will cause an unreliable spark. Be sure the area near the tip of the electrode/sensor on the burner tube is clean right down to the metal with proper gap.
 

John From Detroit

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When I press the on button, I get the auto light. A second or two later I hear a click and the gas light comes on. After that one of two things happen. Either the unit lights, or it goes sends gas to the burner for 20-30 seconds and then shuts down. This is when the check light comes on. During this 20-30 seconds, the is no spark from the igniter. I can smell the gas, so I'm thinking that part is ok. Just no spark at times. I did order the repair kit for the thermistor, plus I had ordered a thermocouple. Is there a way of testing the igniter, or the control box? There isn't really anything else.
Lights, burns 3-5 seconds, shuts off, tries again and again locks off turns on fault light.

That indicates a flame sense issue.. The flame sensor (Also the spark rod on many RV systems) and the control board, and the wire that connect them are suspects 1,2 and 3 not necessary in that order.
 

shelad06

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Nov 28, 2021
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Location
Yuma Az
I replaced the igniter. Fired right off. Then after about an hour, she fired right off again. But she has fooled me before, so I will wait a day or two for a final analysis. Lol
 
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