fridge "Igniter / re-igniter Module" testing ?

[tri5ron]

Hello all,
Well the woe's of this Dometic RM2852 fridge continue to haunt me.
It started as the typical questions of why the fridge will run on AC power, but would not light automatically when switched to gas.

After extensive testing and communications with Randy at BestConverter, and Tech Support at Dinosaur Electronics, we replaced the OEM control board with a Dinosaur board.
That seemed to correct the problem and the fridge did light on gas, and function properly for only 2 trips...
...and now it is back to not automatically lighting (and/or) RE-Lighting on Gas.

I CAN manually light the burner and it will continue to run/burn until the fridge gets cold and it cycles off.

Then it will not relight it self when it should cycle back on. (I have verified this several times), by removing the interior temp sensor from the cooling fins, to make the fridge "think" it was warming up inside, and therefore time to RE-Light itself.

I have checked the Batteries and they are fully charged.
I have replaced the Igniter
I have replaced the control board
I have verified proper voltage to the gas valve solenoid
I have verified gas flow (it lights manually just fine)
I have verified proper voltage TO the "Ignighter / RE-Ignighter Module" (this module has not been replaced and is OEM)

I am now GUESSING / suspecting, the Ignighter Module to be bad, and I am asking for in for advice on how to test it.

I have tried testing for output voltage of the Module, (to the Igniter connection), but I dont really know what I should be seeing there.
I am ASSUMING I should be seeing a few High Voltage pulses coming out of the module to create a spark at the igniter and gas burner. before the Dinosaur board senses the thermo-couple is NOTgetting hot,... and then shuts off the gas flow valve via the solenoid power supply.

So to summerize,
Batterys are full, replaced igniter, replaced OEM board with Dinosaur board,cleaned and checked all wires, connectors, grounds etc.,
It will manually light (using a BBQ lighter held directly at the burner),no problem... but it will not Re-light itself after the fridge cycles off once it was come to temp... and then cycle on and off to maintain that temp.

Can anyone here offer any advice on how to test the Igniter Module for proper function
OR can you think of anything else to try that I have not already ?

As always,
Thank you very much for taking the time to read this and anything you have to suggest.
Cheers,
Ron

[Old-Biscuit]

Freezer HAS to get to at least 10*F before food compartment can get cool

The colder the freezer the better.

The food compartment temp should be 38*F (fin temp roughly 28*F)

The food compartment temp is what regulates cooling cycles (when heat source is turned on/off)

Location of thermistor on fin can affect temp in food compartment by 6*-8*F by sliding thermistor UP on fin for COLDER temp and DOWN on fin for Warmer temps
(The RM2852 has an Auto Temp Control.....no temp setting adjustments----so moving thermistor can affect thermostat control)

[tri5ron]

tri5ron wrote:


... it will not relight it self when it should cycle back on. (I have verified this several times), by removing the interior temp sensor from the cooling fins, to make the fridge "think" it was warming up inside, and therefore time to RE-Light itself...

Thank you all for your VERY detailed suggestions and help. This is what makes the ORF such a great place to be.

OK,... so I THINK I have figured out what was going on with the fridge, (and if I am correct, I feel like such a dummy) :S :h

As you can see in my above quote from my original post,
I DID remove the internal temp sensor from the fins, to warm it up and simulate the fridge warming up and needing to re-light the burner...

BUT !,...
I did not use warm water or anything to make SURE it was REALLY getting warmer.
What I did was, I removed it from the fins, and warmed it up with my hands for a minute or so. I am NOW thinking that I did not get it as warmed up as I had originally thought.

In my (very weak) defense,... I will state that it was near midnight, I had been varmint hunting all day in the field, I was tired, hungry and not double checking my steps.

OK,... so you may ask,
"Ron,... So WHY do you NOW THINK the internal temp sensor was not
getting warm enough in your hand ?"

Well I'm glad you asked :B

This is not actually MY RV.
It belongs to a Senior Citizen friend of mine, who often relies on me to fix his "Stuff" whenever anything goes awry, ... (or he THINKS something is awry). This is usually only a day or two before he is trying to head out on a trip,...
he THINKS he has a problem,
he THINKS he is doing everything right,
he THINKS he understands the function or operation or system,
... and then he tries to work it (or "fix it") himself.

Lately, more often than not, I find that it is more his "operator error", (or complete lack of perception or understanding), that is actually the cause of a "problem".
(When will I ever learn to remember this :Z :S ) LOL

OK, So last night after driving home from my hunt, exhausted,
I met him at the RV.
He had it plugged into shore power all day to get the fridge cooled down on AC. The freezer was somewhere around 0 to -0 degrees, and I dont know how cold the fridge was, but it was also WAYYY TOOOO Cold. (maybe somewhere around 20 degrees).

He had told me he had "Tried Everything" but it would not run on gas. (again,... this is where I SHOULD HAVE remembered that he may not actually fully understand the equipment or it's operation),...
... certainly my bad.

So after spending about 45 minutes messing with it, doing my "hand warming thing" to the internal temp sensor, and only getting it to light manually,... I told him we were going to shut it all down, turn it off, leave the doors open for the night, go get some sleep, and look at it again in the morning.

This morning, with the entire fridge/freezer backup to around 70-75 degrees, I plugged into shore power. turned on the fridge power, set the selector to "Auto" and waited 10 minutes to allow the electrical element to start noticeably warming the flue housing.
Then I unplugged the shore power... and guess what ? ? ?
It immediately kicked over to gas, LIT ITSELF, and was burning just fine on gas with a clean pretty blue flame !
( Well IMAGINE THAT !)

SOooooo,... I plugged back in the shore power, and Waa-Laaa,...
... the flame goes out.
4 or 5 more times of plugging in and unplugging, and all functions just as it should.
(can you all see through the computer right now to watch me slapping my forehead ? ? ?)
So I SUPPOSE, that I apparently DID NOT have the interior temp sensor as warm as I THOUGHT it needed to be, and the only real issue was the fridge was just so darn cold that it would not light itself until it got a bit warmer than I had it.

Anyway,... I felt I owed it to you all to report back with these results. Thank you all for the help.

What do you all think about adjusting the Dinosaur Board's Temp adjustment, to make it so the freezer only goes down to 25-30 degrees, and just let the fridge end up at whatever temp that makes it?
My opinion is that the fridge never really NEEDS to get much colder than 35-40 degrees.

Your thoughts ?

[Old-Biscuit]

Yellow wire from lower circuit board (P3 pin 2) is DC POS to gas solenoid valve AND to reigniter

Black wire from reigniter is DC NEG.

Should have have same DC Voltage on Yellow to Black at reigniter as DC at terminal block during the 6-8 seconds that gas valve gets DC Voltage (trial for ignition)

Got good voltage to reigniter
*Pull High Voltage Cable off reigniter -----uses a good wire to ground and check for spark (NO spark...bad reigniter box)

Got a good spark
*Pull High Voltage Cable off electrode and hold end to ground to check for 'spark' (No spark..bad High Voltage cable)


CAUTION: Just like gas engine spark plug wires.....hold with insulated pliers so you don't get ZAPPED



Good spark.........
Electrode out of position.......too large/small gap etc

[doxiemom11]

Is the thermistor working? Not calling for cold so the gas doesn't relight?

[ScottG]

Eyebrow board not calling for cold.
And it's the only thing you haven't replaced! 😉