Norcold board - is there any hope?

[chasfm11]

OK, before I start, I'll admit that I'm way ahead of myself. We have an N821 that runs great on electric and will not run on propane. I've done the tighten the ground, clean the electrode lead connection and all of that and it still fails.

On propane, ignition occurs immediately after the spark and there is a solid blue flame. It lasts about 45 seconds and then the valve closes and the flame goes out so I know that it is flame sense problem. I've pulled the igniter and cleaned it and tonight, I ordered a new igniter. I figure that there is less than a 5% chance the new igniter will fix the problem but for $14, I had to try.

Let's assume that I'm correct - it is the board. I know that ASAP has my board for $199+shipping. Is there an alternative? I read the thread from late last year about relays on the board. Is the failure likely to be a mechanical problem where the relay is just not transferring or an electrical one where the relay contacts are not making.

The good news is that I have lots of time. We won't need the 'fridge to work on propane again soon. I figure that I can always order the board but would like to play around with possiblities before I do.

All input welcomed.

Charlie

[RJay]

It looks like your on the right track if it's not the spark/sense electrode it's the power board. Here's hoping its the spark/sense electrode.

[RV Wizard]

Charlie, you would be suprized how many times I find a bad electrode. I think your 5% of it being bad is low. Good luck and keep us posted.

[RV Trax]

Verify that the electrode wire is exiting from the main board. Some unit use a small external igniter that costs about $30.00. Also verify the electrode gap. I always bang on the flue to verify that there is no rust falling into the flame area. If there is, it will need to ne cleaned. Most problems like this are from the electrode, dirty flue, thermocouple (if equipped) or the igniter/sense circuit.

[chasfm11]

Thanks for the replies. Mike, I hope that you are right and that the electrode does fix it. At @$23 including shipping, it is an inexpensive solution.

Yes, I've been through the banging on the flue, cleaning the burner and checking the gap steps. Since the flame is starting and burns very well, I dont' see how any of those can have an influence on flame sensing. What am I missing?

How does the electrode pass the flame sense back to the board? I'm assuming that the flame heats the wire and that somehow affects the state of solid core part of the igniter, changing its resistance.

I'm hopeful that I get the part by the weekend and can upate after that.

Charlie

[lpasekof]

Have you looked at replacement boards from Dinosaur Electronics? They make replacement boards for various Dometic, Norcold, Onan, Atwood refrigerators, generators and water heaters. I replaced one on an Atwood water heater a number of years ago. Worked GREAT and about 1/2 the price of Atwood.

Dinosaur Electronics Home. High quality circuit boards for RV appliances.

[chasfm11]

Well.....the igniter arrived today and I installed it..... no joy.

I decided that I had nothing to loose so I removed the board and carefully examined it. There are no signs of burned components or the normal electrical component failures. I worked on large mainframe computers for year and am familiar with many of the common failure sights.

I tried wrapping on the relay. Now, the gas valve will not stay open to produce the constant flame. Tonight, I ordered a Dinosaur replacement board from ASAP. The good news is that they are about $50 cheaper than the end of last year.

I should have the board by the beginning of next week and be back in business. Thanks again for all of the inputs.

Charlie

[Gary RVRoamer]

Let us know if that solves the problem, ok?

[RV Wizard]

Charlie, sorry to hear the control board is the culprit but a Dinosaur is your best replacement. You can go to the "Files" button between Vendors and Blogs and download a file I have put in for downloading called Flame Rectification Sensing if you still want to know how this works. Keep us posted.

[chasfm11]

Quote:

Originally Posted by Gary RVRoamer Let us know if that solves the problem, ok?

I promise you, Gary, that if the board doesn't fix this problem, you will hear the TX explosion in FL! I cannot imagine why it wouldn't.

I went through this a couple of years ago with our Atwood water heater. The board fixed that one. I suspect that our parking the RV outdoors in the hot Texas setting sun "cooked" the electronics on the passenger side. The RV is in a barn now so we shouldn't have that problem any more. There is still a furnace on the passenger side that is functioning properly but that board doesn't get the full blast of the sun since it is mounted sideways. I could be totally wrong and this is all just bad luck

[Dr4Film]

Quote:

Originally Posted by chasfm11 Tonight, I ordered a Dinosaur replacement board from ASAP. The good news is that they are about $50 cheaper than the end of last year. I should have the board by the beginning of next week and be back in business. Thanks again for all of the inputs. Charlie

What specific board number were you looking for as I have a brand new spare control board #628661 for a Norcold frig that I will never use as I now have a different unit. I will most likely try to sell in on eBay or craigslist.

Dr4Film ----- Richard

[chasfm11]

Thanks for the offer, Richard. The OEM part number from Norcold for mine was 632168001 and I don't believe it is a match for yours. Unfortunately, your offer comes to me after I've already paid for the dinosaur board but perhaps it can help someone else.

[chasfm11]

Well, there is no joy here. Here are the events:

1. Dinosaur board arrived in today's mail.
2. Put the jumper on 67, installed board in MH
3. Turn 'fridge on. Sensed no A/C power, fired the propane, flame, flame sense...it's working!!!. Hallelujah! Problem solved.
4. Decided to test the board cutover so put A/C power to MH, turned the 'fridge on and it sensed A/C power and started cooling. Great!
5. Removed A/C power (pulled the plug at the 'fridge. Board recognized the loss and started to fire the propane. Wait....no propane...flame won't light.....
6. Checked voltage to gas valve. It shows as erratic and changes ever time the spark sequence starts. Later determined that the spark sequence was driving my cheap meter crazy. Just for fun, I used a spare 12v battery to power the gas valve directly as soon as the spark sequence started. Every few seconds, there would be a large pop as the gas ignited but it only lasted a split second. Flame never lit

Bummer.

I'm definitely not getting gas. There is no propane smell at all. I powered the gas valve directly from the spare battery and stuck my nose in the chimmney. No gas smell.

I guess the next step is to bleed the propane off the RV and then remove the gas valve. With the pipes open, I should be able to see whether there is a physical opening for the gas to flow through, right? I'm not expecting it to be too much of an opening since there isn't much of a flame. Maybe there is spider web or something in the valve outlet.

I can definitely hear the valve soleniod picking so I'm getting a mechanical transfer from the voltage. Before anyone asks, I turned on all 3 burners on the stove at the same time and there is a solid blue flame on all of them. Fridge is right next door.

Oh, well. The good news is that I'm not under the gun to fix it. We just came back from a trip and won't be camping again for a couple of weeks. When we do, we can cool the fridge on electric, drive to the CG and power it from A/C there, too.

Input is always welcome.

Charlie

[chasfm11]

Update at 9:30pm EDT

What a difference an hour or so can make! I followed the game plan that I laid out in the earlier post and purged the propane system. I removed the gas valve and, as I suspected, I could not my blow my breath through it with the coil energized. I removed the plug from the out side and tried again. It worked. I replaced the plug and the valve was still working.

While I had that much apart, I went ahead the pulled the burner. It had a bunch of crude in it. I used a broom straw to clean the orfice and then I put everything back together and tested. While it took it to the end of the spark cycle, fire it did and it continued to work. I used the panel to swap to A/C and then back to propane. No problems - the propane fired right away each time.

Because I just had to know, I re-installed the original board. No flame sense.

I'm probably going to test some more tomorrow but it looks like everything is working fine. I cannot tell you how relieved I am. When the propane didn't work the second time after the new board was installed, I definitely was not a happy camper.

Alls well that ends well.

Charlie