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Topic: Thermocouple for RM3662 fridge (Read 491 times) previous topic - next topic
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Thermocouple for RM3662 fridge
I just ordered a 2932052018 Thermocouple from Amazon for $22. Amazon had a few to choose from ranging all the way up to $70. I could have bought one from Camping World for about $90.

Not sure if this is  an  item  I should not have skimped on but I cheaped out and got the lowest priced one anyway. Are all thermocouples  created equally?
Steve
2003TK
Re: Thermocouple for RM3662 fridge
Reply #1 –
Are you sure the RM3662 has a thermocouple, I remember ours only having the spark ignitor which also doubles as a flame sensor.
What problem(s) does the refrigerator exhibit?

Larry
Larry
2003 23.5' Front Lounge, since new.  Previously 1983 22' Front Lounge.
Tow vehicles  2020 Jeep Wrangler Rubicon, 2001 Jeep Cherokee
Photo Collection: Lazy Daze
Re: Thermocouple for RM3662 fridge
Reply #2 –
"Are you sure the RM3662 has a thermocouple, I remember ours only having the spark ignitor which also doubles as a flame sensor"
---
The exploded parts diagram in the manual for the RM 3662 (that is in my 2003) shows the "burner housing" (A) containing an electrode (E) and a thermocouple (T).

(Larry, the "spark ignitor"that  you refer to is the "electrode", yes?)
2003 TK has a new home
Re: Thermocouple for RM3662 fridge
Reply #3 –
Quote from: Joan  - 
The exploded parts diagram in the manual for the RM 3662 (that is in my 2003) shows the "burner housing" (A) containing an electrode (E) and a thermocouple (T).
the "spark ignitor"that  you refer to is the "electrode", yes?)

Joan

The RM3663 was replaced several years ago. I was looking at online parts lists and didn't see a thermocouple, only the electrode. It may be listed elsewhere.
Does your RM3662 has one?

Larry
Larry
2003 23.5' Front Lounge, since new.  Previously 1983 22' Front Lounge.
Tow vehicles  2020 Jeep Wrangler Rubicon, 2001 Jeep Cherokee
Photo Collection: Lazy Daze
Re: Thermocouple for RM3662 fridge
Reply #4 –
According to my records, I replaced the thermocouple of my RM3662 eight years ago, so it definitely does have one. I paid $37.04 at that time.

I had been having trouble with the fridge failing to light or to stay lit. At first I figured it was a case of oxygen starvation, since I was camping at 10,000 feet. But as it turned out, that wasn't the cause.

I tried sandpapering the thermocouple, moving it closer to the flame, and even replacing the fridge's controller board with a Dinosaur board. I took out the thermocouple and tested its resistance, and it seemed to be within tolerance. I checked the propane pressure with a manometer; it was the recommended 11 inches of water.

Installing a new thermocouple cured the problem, and from then on the fridge worked fine, even at 11,000 feet.
Andy Baird
2021 Ford Ranger towing 2019 Airstream 19CB
Previously: 1985 LD Twin/King "Gertie"; 2003 LD Midbath "Skylark"
Re: Thermocouple for RM3662 fridge
Reply #5 –
Yes as others have noted the RM3662 does have a thermocouple. While looking for a part number I also noticed some parts diagrams were shy on the thermocouple.

I sanded mine and it worked for a bit but seemed to fail again. Figured it  was time to change an old  part. However I'm not positive that it is the  true culprit at this time. Last time I used the fridge a week ago  it wouldn't light. I did get it to work by manually lighting the burner. During that 7 day trip I did have to manually light it one additional time. 

The thermocouple was delivered today so I'll get it installed and report back. Do igniters fail very often? I've never had to replace one before.
Steve
2003TK
Re: Thermocouple for RM3662 fridge
Reply #6 –
Quote from: 73gitane  - 
Yes as others have noted the RM3662 does have a thermocouple. While looking for a part number I also noticed some parts diagrams were shy on the thermocouple.


I missed that one, checking, our old RM3662 had a thermocouple and it was replaced a couple years before the cooling unit failed on the first day of a four week trip. A DM2662 replaced it.
Newer Dometics do not have thermocouples, instead they use a flame sensor that detects the heated plasma, between the electrode and ground, when the flame is heating the gap and ionizing the moisture in the air. If the plasma isn't present, the control board detects this and tries to re-light the burner.

Larry

Larry
2003 23.5' Front Lounge, since new.  Previously 1983 22' Front Lounge.
Tow vehicles  2020 Jeep Wrangler Rubicon, 2001 Jeep Cherokee
Photo Collection: Lazy Daze
Re: Thermocouple for RM3662 fridge
Reply #7 –
Hi Steve. In my limited experience, the insulating ceramic base on the igniter gets coated with a fine film of dirt. When it is humid, the dirt becomes conductive enough to conduct electricity, and shorts out the spark.  I've cleaned mine with a clean toothbrush and alcohol. Blew it off with compressed air and all was better for a few years.  I've heard that the insulator can get a crack in it that does require replacement, but I haven't had that happen to me (yet).  While you've got the covers off and compressed air, it's a good time to blow rust particles out of the burner screen.   RonB
RonB (Bostick) living in San Diego
Original owner of "Bluebelle" a '99 TKB
Re: Thermocouple for RM3662 fridge
Reply #8 –
Thanks for the tip on  cleaning the igniter Ron. I went ahead and did that while I replaced the thermocouple. All is good now and the fridge is working as expected.

Steve
Steve
2003TK