OK then disconnect one wire from the pressure switch and try again. I cannot see how the pressure switch got damaged by the ignitor blowing. I have never seen a ignitor have that kind of a problem and I have seen many. Usually they crack after a period of use. I have seen cases where they were broken in the bottom of the unit but I never figure they blew up.

The pressure switch contacts could be burnt colsed for some reason. You did not have that problem before the ignitor when bang. Strange very strange.

I will be signed out for a few hours I believe. Post results of your testing.

The ohmmeter says that the switch itself is open. Which is what the schematic diagram shows it should be. Normaly open. With the switch in the circuit it gives error pressure switch stuck open. With the pressure switch removed it gives the same error, and with the pressure switch removed and the leads shorted together it gives the error "pressure switch stuck closed". Note since the explosion I have not heard any of the fans come on. And I have been removeing power from the unit between attempts

OK so I slept on it and came to the realization that as I said before since the explosion, the fans have not come back on. It appears that maybe I have lost a relay on the control board, as I do not have the 240v being sent to the inducer fan. Without that fan blowing the pressure switch will never be happy. Is this correct?
You wouldn't happen to have a schematic of that control board would you? These are all the numbers I can find on that board.

624631-0

1012-955a

1012-83-9555a

Nordyne 0241

The boards are only serviceable as a assembly. The factory keeps the control board info to themselves. Usually Nordyne and all other manufactures have the board and all components manufactured to there specs by a contract vendor.

I am sure some of the parts might be available at a electronics wholesaler.

The pressure switch will not activate if the combustion air fan is not working.

Have you ever heard of losing the control board when the ignitor blows? This really sucks I had it working for 3 seconds then blew up. It must be the control board bad now since the inducer fan is no longer turning on, right? House getting down in the 50s at night, and temps outside still dropping got to figure this thing out soon.

In looking over the wiring diagram I see where they are picking up a ground for the circuit board P1-9 but they are also at L2 which is one leg of the 220 feeding one side of the transformer but as you follow the diagram down they are also calling it a neutral on the circuit board. This puts up a ? Mark for me. If this is the case they are using the ground conductor from the house wiring to be able to supply 120 volts for the ignitor part of the circuit board. Since they have tapped the ground conductor and are using it as a neutral that also gives me another ? Mark for the circuit.

Usually if they are going to tap the ground to obtain a neutral for 120 volts from a 220 volt line they would also require a dedicated ground wire also. With my luck there is probably an exception in the NEC for equipment manufactures.

That circuit board creates confusion.

If they will talk to you Nordyne/Frigidaire might be able to shed some light on this situation. The ignitor blowing up is a strange happening. When the ignitor blew it might have taken out the board so I would be finding out the deal before I would replace the board and ignitor assembly. I have never experienced a ignitor blow up only seen pieces at the bottom of some units that needed service. I wish I were close to your location I would really like to dig into this one. The more difficult to fix the better I like it but trying to work on a unit by posting leaves much to be desired.

Get out the old portable electric heater for now tomorrow you can contact them.

Confusion, yes... that's where I am. That's why I was hoping for a schematic for the board. However, I searched the web over and could find no such schematic, before receiving your explanation for why it was unattainable.

I wish I could help more tonight but I cannot. Try and contact them if you can.

Well thank you for all you have tried to do. You have provided much useful information, and I have learned a lot in this ordeal. I will try, as you suggested, to get ahold of nordyne/frigidaire and see if they will offer any insight. Otherwise I guess I'll continue searching for answers. Thanks for your time, I'll try to post the outcome. Maybe it will help someone else. Or maybe I'll get lucky and someone else will have seen this and add to this thread some more help. Thank you again hvac1000 your assistance is appreciated.

Hope you get it gojng. I hate to say this but you could roll the dice and get a new factory board and a factory ignitor and give it a go.

Hey, I've had the same problem, same unit and everything. And it was just running the blower, just like yours, it sounds like. I finally replaced the board with a universal board, then it would flash me a voltage polarity, or ground problem when I powered it up. I check all my voltages and even added an extra ground clamp, and all was good. So I unplugged the HSI, then it would cycle through and run fine until it was time to ignite and then it would shut down when their was no heat.( cause the HSI was unplugged). That's when I did something stupid, I unplugged the HSI and powered it up, and when it was time to ignite I plugged in the HSI and it all worked good for a minute. The HSI started to glow and then it blew again. And this time it took my new board with it. Im starting to wander if the HSI was arcing to the burner lip cause it does look kind of close in there. If you figure it out, please let me know.

AT last! UPDATE: K.I.S.S.

First thanks to hvac1000 for all the help. I learned a lot.

OK, so I did some more troubleshooting and decided I must have toasted the relay that sends the 240 to the inducer motor and the ignitor. So after carefully marking the wires, I removed them and pulled out the board. Low and behold, when I flipped it over, I found a burnt trace and lots of smoke damage around said relay. So a friend of mine helped me take out the relay and test it and yes, it was testing bad. In case your curious the relay was a T7CS5D-12 . However since I am broke and need to save money I did not purchase a new one, instead we cut the old one open and found that the contacts inside had slag on them from trying to weld themselves together. So we cleaned the contacts with emmory cloth, and siliconed the thing back together, then used tinned copper braided grounding wire to repair the trace. Reinstalled the board and using the original ignitor, fired it back up, and wadayaknow, success! We have heat. Now remember, this all started because I had a corroded contact on one of my limits, which was easily fixed by unplugging and replugging all the blue wires in. so again I must remind myself K.I.S.S. (Keep It Simple Stupid)

Oh Yeah By the way, DUSTINHD by any chance did you change your his before you noticed the possibility of arcing? Also how much was the universal board? Just curious...

Yes, I did the same thing you just did. I fixed my original board's relays, and replaced the HSI. But I wasn't as lucky. When I fired it up, the HSI blew a 2nd time. And completely fried the board. That's when I got the universal board.(around 170$) I was told they couldn't get me the same board. It was obsolete or something. The new board is a lot more micro elec. And can't tell much from it.

Did you by any chance have to modify the mounting bracket to replace the his?

Quote:

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Originally Posted by ichosethis1

AT last! UPDATE: K.I.S.S.

first thanks to hvac1000 for all the help. i learned a lot.

ok, so i did some more troubleshooting and decided i must have toasted the relay that sends the 240 to the inducer motor and the ignitor. so after carefully marking the wires, i removed them and pulled out the board. low and behold, when i flipped it over, i found a burnt trace and lots of smoke damage around said relay. so a friend of mine helped me take out the relay and test it and yes, it was testing bad. in case your curious the relay was a T7CS5D-12 . however since i am broke and need to save money i did not purchase a new one, instead we cut the old one open and found that the contacts inside had slag on them from trying to weld themselves together. so we cleaned the contacts with emmory cloth, and siliconed the thing back together, then used tinned copper braided grounding wire to repair the trace. reinstalled the board and using the original ignitor, fired it back up, and wadayaknow, success! we have heat. Now remember, this all started because i had a corroded contact on one of my limits, which was easily fixed by unplugging and replugging all the blue wires in. so again i must remind myself K.I.S.S. (Keep It Simple Stupid)

oh Yeah By the way, DUSTINHD by any chance did you change your hsi before you noticed the possibility of arcing? also how much was the universal board?? just curious.........

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Question?
Does the ignitor in that unit use 240 volts ? If so they have there parts diagram on my electronic parts catalogue wrong. It is listed at 120 volts.

I am real familiar with how you did the repair. Many years ago I used to etch my own boards for a few projects and then run through the solder tray. I have great respect for a person who is bucks down when they can figure out the problem and do a work around that gets the job done and is safe.


If you want to stock the relay just in case there are usually some on eBay like here

http://cgi.ebay.com/5-Potter-Brumfie...QQcmdZViewItem

Looks like 15.00 gets you 5 of them delivered.

Sometimes the emery cloth routine just buys some time and it might fail again so CYA
To make sure you have a spare.

In today's world a service person or company could never just replace that relay due to liability concerns but as a individual you can since it is your unit.

Once again I would check on that ignitor voltage coming off the board and if it is 220 for sure please let me know. If I were you and it is 220 I would be trying to find a spare since they also have a tendency to fail and I would have one on hand just in case.


Most of the posts from folks seeking help are mundane in nature.This one was actually enjoyable especially since you took the time to actually figure out the problem and effect a repair. Most folks would never attempt this since they usually do not have the broad knowledge necessary to make a repair like that on a circuit board.

Very glad you got it going.

You get the Genius award and the Macgyver award for ingenuity!

Quote:

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Originally Posted by ichosethis1

did you by any chance have to modify the mounting bracket to replace the hsi?

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No, but it looked a little different. Im now thinking about the HSI being 240v instead of 120v. That would make since.

Quote:

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Originally Posted by ichosethis1

did you by any chance have to modify the mounting bracket to replace the hsi?

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Im going to try to fix the old board, on more time, before I spend any more $. And see if Im getting the correct voltage fore the HSI, cause the universal board would not let me check anything. It was set up to be so protective that it would just shut down any time you checked voltage or anything. Ive already ordered some parts for the old board and will know more in a few days.

Quote:

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Originally Posted by ichosethis1

did you by any chance have to modify the mounting bracket to replace the hsi?

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That was messed up, my unit did take a 230v HSI. When every where I went when they looked up my unit they called for a 120v. I fixed the board and was able to get heat again.