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chasfm11 · 07-28-2013, 09:27 AM

I have Norcold 'fridge model N821, Serial 765118GB

The symptom is that it cools fine on AC but gives me an "F" code on LP.

Actions:
1. Verified propane. All three burners on the stove run at the same time with solid blue flames
2. Opened fridge burner compartment. Everything is clean - no spider webs, rust. Removed and reinstalled both the igniter and the burner, snugging down the screws (in case there wasn't a good ground).
3. Checked both 5 amp fuses on the board.

When I switch modes to LP, there is no sound from the ignitor. I opened the output line from the gas valve to the burner. When the control board is supposed to be sending gas to the burner, there appears to be none coming out. I have a combustion gas detector and it never peeps. There is simply a timeout then the "F" code sets.

This fridge is 13 years old but in 2010 I had a similar problem. I replaced the original board with a Dinosaur.one. I was having intermittent sticking problems with the gas valve so I replaced that, too. From 10/10 until earlier this month, the unit worked fine, switching between LP and A/C without problems.

Logic tells me my Dinosaur board is bad. My mind tells me that is unlikely.

What else is likely? I really REALLY could use some fresh ideas.

Thanks,

Charlie

jesilvas · 07-28-2013, 09:34 AM

Get a 12V test light. Be plugged into 120V power, with LP turned on. Turn on the refr on auto. Go to the back of the refr outside, ground test light, get ready to test wires at gas valve. Unplug 120V cord from outlet so that refr tries to go to LP. You SHOULD get 12V at the gas valve which means at the board connection for gas valve, it should be putting out 12V also. That'd be my first stop.

jerichorick · 07-28-2013, 09:56 AM

jesivas is correct. Check if the igniter is fiering. Do you smell any gas at the burner when it is calling for service? This might not be a valid test if air is in the line. A thread held near the orphus will move it there is movement from it.

chasfm11 · 07-28-2013, 10:03 AM

Pulled the leads off the gas valve. Hooked them to a meter. Pulled the A/C cord. No 12 volts.....ever.

I have a spare lawn mower battery. I connected it to the gas valve and then used a manual igniter. Burner lights and burns with a solid blue flame.

I guess I have my answer. I thumped both relays on the Dinosaur board with my finger, thinking one of them might be sticking. No joy.

Bummer.

chasfm11 · 07-28-2013, 10:04 AM

Quote:

Originally Posted by jerichorick

jesivas is correct. Check if the igniter is fiering. Do you smell any gas at the burner when it is calling for service? This might not be a valid test if air is in the line. A thread held near the orphus will move it there is movement from it.

My original symptom is that the igniter never fires. I'm standing outside right by it when I pull the A/C cord. Nothing. No sound of any kind. I was expecting at least a relay to click

As I stated in my OP, there is no gas coming out of the valve when it is supposed to be. I didn't smell any but I put my detector on just in case my sinuses were getting in the way. It didn't smell anything either.

"007" · 07-28-2013, 10:27 AM

The AC leads are only for the electric elements no relays involved.
Take the ignition leads off the control board and check for 12v on the two pins, the spade clips may need some cleaning for ignition to work and by just removing and placing back on pins you may already have done it.
The ceramic element on end of rod may need cleaning so it sensors the flame when you get one to keep burner on.

Cleaning your burner.

FRIDGE EDUCATION ----LINKS FOUND IN TECH TIPS STICKY

jesilvas · 07-28-2013, 10:32 AM

Sorry, shoulda clarified: don't remove the leads from the gas valve, but leave them on the valve just enough so you can test for 12V there.
You can test the gas valve solenoid for resistance when you remove terminals from it. Just ohm out across it's two terminals.

chasfm11 · 07-28-2013, 11:06 AM

Quote:

Originally Posted by jesilvas

Sorry, shoulda clarified: don't remove the leads from the gas valve, but leave them on the valve just enough so you can test for 12V there.
You can test the gas valve solenoid for resistance when you remove terminals from it. Just ohm out across it's two terminals.

The gas valve works when I apply 12 volts to it directly from a spare lawn mower battery. I can hear it click when it comes on .

The coil on the gas valve measures 100 ohms with a reasonably good meter.

I tested the sequence with leads to the gas valve still meter leads themselves were making contact that way. I pulled the wires off the gas valve to check that that was the case.

There is a very faint click coming from the board about 10 seconds after I pull the A/C plug to force the switch to LP. The ignitor is definitely not trying to fire. The gas valve click that I heard with the aux battery is also not there.

I've pulled and cleaned every contact going to the board.

chasfm11 · 07-28-2013, 11:15 AM

Quote:

Originally Posted by 007";1661411]The AC leads are only for the electric elements no relays involved.
Take the ignition leads off the control board and check for 12v on the two pins, the spade clips may need some cleaning for ignition to work and by just removing and placing back on pins you may already have done it.
The ceramic element on end of rod may need cleaning so it sensors the flame when you get one to keep burner on.

[URL="http://blog.rv.net/2008/04/maintenance-cleaning-a-norcold-burner/

Cleaning your burner.[/URL]

FRIDGE EDUCATION ----LINKS FOUND IN TECH TIPS STICKY

I'm expecting the relays to change states when the control board goes from A/C to LP.

There is only one igniter lead. It goes to the high voltage output on the board. I removed that connect and cleaned it. As I said earlier, I also removed both the igniter and the burner in case the ground path was somehow open or at a high resistance.

I'm not getting any flame because the igniter never fires to try to create one. You may have a point that somehow, the igniter is telling that board that there is a flame and therefore not to go through the ignition sequence. I'm not sure how to check if that is happening. I wonder if disconnecting the igniter lead from the control board might get the gas valve to come on. That would say that the igniter is bad, I think. I'll try that test.

Thanks to all for your inputs. I'm doing a lot more things to assess what is happening than I was when I made the original post. Please keep the ideas coming. I can survive with the fridge working on A/C only but I'd rather not have to fire the generator on hot days to keep it working.

jesilvas · 07-28-2013, 11:37 AM

My next thought, like you said, is a board issue.
I know on the Dino Boards, they make one model to replace 7 or 8 different boards and there is a small pin jumper that you have to move depending on what model board you're replacing.
Had one come in that wouldn't work on LP for some reason. Found that for three years, it had been on Dino's "test" mode, and not the correct board but worked until just one day, all of a sudden. Fixed the pin jumper, and it was great.

"007" · 07-28-2013, 11:46 AM

Put your spare battery 12v to the 12v leads feeding the control board and see what your results will be, have all other connections back where they belong.

chasfm11 · 07-28-2013, 12:08 PM

Quote:

Originally Posted by "007"

Put your spare battery 12v to the 12v leads feeding the control board and see what your results will be, have all other connections back where they belong.

Thanks. I had done that. The results are the same. I confirmed the normal input voltage at over 13vs (RV is plugged in to shore power and convertor is on at this time) but I thought I'd check it. This failure started yesterday while I had the RV unplugged and parked outside, doing maintenance. I thought then that it could be bad house battery voltage but the same failure continued after it was back in the barn and with the shore power connected. I connected my lawn mower battery after I tried the gas valve. No joy.

I also got the same results when removed the ignitor connection from the board. It just isn't even trying to light the LP.

A quick analysis shows that I'm out of warranty on this board. So I'm going to have to buy another one. I'm just trying to make sure that I absolutely positively need one before I drop $250+.

"007" · 07-28-2013, 12:34 PM

You do not need battery to relay you need it to the 12v feed to the board with all moved wires in place as they should be.
Some fridge have a 12v connecting block at base of fridge feeding the control board.

"007" · 07-28-2013, 02:10 PM

You say the fridge is working on ac than the board is functioning for AC portion of control board.
The board has 12v's to do that.
There is a 12v fuse on board and it must be good for board to operate.
I would remove 12v fuse and see if AC operation stops, than replace and see if LP will operate when you pull the AC element plug to fridge.