Dometic fridge won’t stay lit

[AprilnJohn]

Hoping someone here can help as we’re in the midst of our vacation.
Dometic RM2652 fridge. Pilot lights instantly. Burns for 15 sec or so and shuts off.
I downloaded the manual.
I checked the burn tube (beautifully clean), flue, and orifice.
I’ve gone through the tests and everything seem ok except for the thermocouple.
During pilot it only puts out 19mv. Spec says 25-35mv.
I was able to pick up another thermocouple and it does the exact same thing with almost the same test readings. Maybe up to 20-21mv.
Any suggestions? Can I bypass or fool the thermocouple?
I’m using my generator during generator hours to try and keep things cold but obviously it’s not the best setup.
I appreciate any help.

[Old-Biscuit]

P3 connector
Pin 1 ---White Wire----GROUND
Pin 2 ---Yellow Wire---12V DC+ to gas valve solenoid AND reignitor controller
Pin 3 ----empty
Pin 4 ---Blue Wire---TEST Port (used to test that circuit board is sending DC Voltage to gas valve/reigniter

Dino Board
THREE different boards
Check which Dometic Board you have then pick the right Dino
Dino boards for RM2652

[dougrainer]

AprilnJohn wrote:
I hear ya.
So keeping the flame going I was able to get the thermocouple up to 33mV and the board still de-energizes the feed to the solenoid.
So now I have this question on the replacement.
The original Dometic board?
The Dinosaur P-711 board?
Now if I read it correctly, the P-711 is a 3 way. Can I use that feature?

You can use Dino or Dometic. Years ago Dino was a better board. Now, both Dometic and Dino have the same deal. If Dino is cheaper, go with Dino. Doug

[AprilnJohn]

I hear ya.
So keeping the flame going I was able to get the thermocouple up to 33mV and the board still de-energizes the feed to the solenoid.
So now I have this question on the replacement.
The original Dometic board?
The Dinosaur P-711 board?
Now if I read it correctly, the P-711 is a 3 way. Can I use that feature?

[dougrainer]

The Blue wire is capped and NEVER used on any Dometic system. As I stated, DO NOT POWER THE YELLOW WIRE OR DO ANYTHING TO BYPASS THE THERMOCOUPLER. IT IS A SAFETY CONTROL AND IF THE FLAME WENT OFF, YOU WOULD HAVE A MASSIVE LP LEAK. Doug
PS, just get a new rear control board

[AprilnJohn]

So as I’m looking at it, there are 2 yellow wires (+) on the solenoid. One from P3 and the other to igniter. What part controls the power? One of the relays?
If I were to supply power to the yellow wire, would it stay running?

[AprilnJohn]

Thanks for the input.

Still not working. Cleaned grounds and checked resistance.
DFord it sounds like you have a different manual as this isn’t a 3 try setup. One try and done.
I have power to igniter and solenoid.
Flame sense circuit only gets up to 20mV
Anyone know if the P3 blue wire is supposed to be connected to anything? I get 12V on it when running but nothing when it shuts off.

[DFord]

DOMETIC DIAGNOSTIC SERVICE MANUAL
PAGE 17

gas mode

note: All current Dometic control boards are 3 try systems in the gas mode. There is a 2 minute purge cycle between each trial for ignition. Flame failure will take 6 to 7 minutes. Verify that the following components are good: upper circuit board, thermistor, wire harness and 3-amp fuse. First, check for voltage during trial-for-ignition at Plug 3, Terminals 1 (white Wire -) and 2 (yellow wire +) to the igniter and solenoid. If no voltage is present change the circuit board. If voltage is present, check for voltage at the igniter and solenoid. If no voltage is present, check the wires. To check the flame sense circuit of the lower circuit board, The millivolts meter should read between 25 to 35 millivolts with the gas flame burning. When the power module senses the loss of flame (thermocouple voltage below 13 MVDC) the 45 seconds trial for ignition period is started. Turning the refrigerator OFF–ON while operating in the gas mode may cause a check light. Operate the refrigerator on GAS and measure the millivolts between J3 (NEGATIVE) terminal original control or J4 current control and the other wire (POSITIVE) connection from the thermocouple.

note: A loose ground will create erratic or no
gas operation on all systems.

gas mode Integrated Igniter

Verify that the following components are good: upper circuit board, electrode with cable, wire harness and 3-amp fuse. Units that have integrated igniter do not have a thermocouple. The igniter senses the flame thru the electrode and communicates with the lower main control. The integrated igniter used on certain Dometic model refrigerators operates on 12 volt DC thru the control board. On gas operation the igniter senses the resistance through the flame between the electrode and burner. When there is no flame at the burner, the resistance is high and the igniter begins sparking to light the burner. As soon as the flame is lit, the resistance between the electrode and burner drops and the igniter stops sparking. The resistance is monitored by the igniter, and, if for any reason the flame goes out, the igniter begins sparking until the burner is lit. This insures that the flame will always be lit when desired. The integrated ignition system is also a three try control. Turning the refrigerator OFF-ON while operating in the gas mode may cause a check light. If you have voltage to the gas valve during trial-for-ignition but no spark and the electrode with cable checks good, change the lower control board.

note: Never engage the gas mode with the electrode cable unplugged from control board. This will damage the igniter on the board.

[John_Wayne]

That's as big as the flame is going to get. Pull the connector off the circuit board and reinstall the connector and see if that will help. Or wipe the circuit board contacts with some alcohol before reinstalling the connector. See if that would help. Also check the ground connection.

[AprilnJohn]

https://www.dropbox.com/s/7ic6u3juc1n9bye/rvfridge.jpg?dl=0

See if that link works with copy and paste.
That’s my burner.
I cleaned the orifice lightly with a toothbrush and jewelry cleaner. Just what she had on hand.

[Old-Biscuit]

LP System Low pressure will cause a 'cool' flame....it can look correct but will not be as hot due to lower fuel/air ratio

LP System should be 11"WC with at least 50% of appliances in service
Pressure testing port on gas valve assembly just after solenoid



Orifice .....
Should be cleaned by soaking in alcohol only (about 1 hr)
Then air dry
NO pressurized air or poking anything thru it
Orifice has a ruby set in center that is laser drilled. Air pressure/poking WILL damage/dislodge the ruby.

[midnightsadie]

have you removed the burner and cleaned? DO NOT POKE ANYTHING in the orfice hole you,ll ruin it. clean with air soap water. your burner flame should be about a inch long nice and blue.

[MARKW8]

The fridge likely needs a control board. My fridge was new in 2000, about 05 I had the same problem. I installed a Dinasour brand board. The fridge is still working.

Mark

[AprilnJohn]

Thanks. It’s in a 2005 Springdale
I linked a pic of the burner if it works.
I tried both of my tanks to see if there is any change. No difference.
I also tried sticking the old thermocouple is the flame of my water heater with my meter on it and got the same results.
The fridge worked before this trip.
***Link Removed***

[dougrainer]

There is NO pilot light. That is the main burner flame. Thermocouplers rarely fail, so, having 2 do the same thing points to a control board problem. NO, there is no SAFE way to bypass the Thermocoupler. It is a SAFETY device. If the burner flame is too low(LP gas pressure slightly low) then the flame will NOT be hot enough to satisfy the Thermocoupler. Doug

What year is your RV?