Hi all, I have a Frigidaire package unit heater/air conditioner and my heat does not work suddenly. All was fine until the night before thanksgiving I came home and the house was down to 63 degrees and the vents were blowing cold air!! The model number of my unit is R4GA-036K072C and apparently it is made by Nordyne. I have tried already changing the ignitor, careful not to touch it, as I had read in one of the forums this is usually the problem, but even the new one does not glow. The original ignitor ohmed out at 176 ohms, while the new one ohms out at about 60 ohms. I have checked the fuses, and they are fine. I have checked for voltages at the step down transformer and they are all there. I have also checked the voltages on the colored wires coming back from the thermistat and they are as follows. Red to yellow 27.5v, red to green 27.5v, and red to white 0v. I am told that there is some safety stuff that must be happy to make heat, and would like to know is there a testing procedure for these things? Like the flame rollout switch and the temp probe, and pressure switch? When observing its operation from outside with the panel off, when I apply power the red status light is on solid for about 3 seconds, then something clicks, and the status light starts blinking about once every second, or second and a half. The exhaust fan is running, and the blower motor stays on and never no matter how I try does it shut off. The only way to stop the blower is to pull the breaker. I have been unable to find any useful documentation, and it is getting very cold in here, any help would be greatly appreciated...

This is your complete manual for service. See what the circuit board is falshing and then see page 26 to see where it takes you with the problem. Keep this for your records. Post back with what is going on. NOTE you might also check to see if the circuit board is putting out voltage to the ignitor.

http://www.nordyne.com/Literature/7086290.pdf

Wow thanks for such a quick response, according to the documentation you provided, it appears I have a fault condition of limit circuit open. How do I troubleshoot this?

Find the limits on the wiring diagram if possible, The limits might also have a reset buton in the center. That info I sent you will show it on the wiring diag.

Thanks for the help, I will study the diagram again and try to figure it out, but I have not been able to find any kind of reset button whatsoever.

Usually the reset is a very small button in the center of the disc limit control. I have no way of finding it for you since I am her and the unit is at your place but follow the wires on the diagram might help.

Bypass one limit at a time(flame rollouts, high limits). Just unhook the wires from the limit, and hook the two wires together. See if the furnace works. If it does, replace limit. This is only a trouble shooting test, do not use furnace while limits are bypassed. Good luck and lets us know what you find.

OK progress? Sort of. After going over the diagrams that hvac1000 was so kind to provide, and following the blue wires, I have found my limits. (no pun intended). I have now, I think, fixed the original problem, being coroded terminal plugs to the limits. And finnally got the sucker to glow. Problem is about 3 seconds after starting glow, it promptly blew up! Now remember this was a brand new ignitor, and I used gloves to install it so as not to possibly touch the thing. So I got my old ignitor back out of the box and re-installed,again wearing gloves, only now after applying power, I get two blinks out of the red light indicating pressure switch stuck open. And nothing further happens.(the blower is finally staying off, yay!) So, what do I do about the pressure switch staying open error? I still have not found any sort of a reset switch in this unit. And as far as I can interpret the schematic, the pressure switch is supposed to be in a normally open state, which the ohmmeter confirms it is.

The ignitor blew up DANG. How much voltage is being fed to the ignitor off the board? That is a 220/240 volt unit but I figured they just used one leg of the 220 which would be 110 to fire off the ignitor. Cycle the disconnect off for 5 minutes then re-energize the unit abnd do a start up cycle. I need to know how much vlotage is being supplied to the ignitor circuit.

Here is your parts list for your unit.


http://www.nordyne.com/Literature/707786m.pdf

You might have been sold the incorrect ignitor??

I have had it off since last post I just re-applied power and the red light still blinks twice. The voltage reading across the ignitor is 15vac

Agreed, may very well have sold me the wrong one as it was a bit shorter. However I have switched back to old ignitor, and now have this pressure switch problem since the explosion

15 volts will not cut the mustard. Depending upon your system they are usually110/120 AC or 24 vlots A/C

Jump the pressure switch to test it. Do not leave run under these circumstances just test.

i have had it off since last post i just re-applied power and the red light still blinks twice. the voltage reading across the ignitor is 15vac


Does your ignitor look like one of these?

Does your ignitor look like one of these?

Or this

Does your ignitor look like one of these?
Yes like 41405

15 volts will not cut the mustard. Depending upon your system they are usually110/120 AC or 24 vlots A/C

Jump the pressure switch to test it. Do not leave run under these circumstances just test.
OK, I just jumped the pressure switch and now I get 3 blinks from the red light indicating that now the pressure switch is stuck closed.

Ok you have a regular one. Standard 110/120 volts. That is the voltage you should be reading at the circuit board going to the ignitor. Try to temp jump the pressure switch but before you do that reset the electric again.

Ok you have a regular one. Standard 110/120 volts. That is the voltage you should be reading at the circuit board going to the ignitor. Try to temp jump the pressure switch but before you do that reset the electric again.
I just tried to jump the pressure switch but it gave me a 3blink pressure switch stuck closed error and did not ignite the ignitor

i just tried to jump the pressure switch but it gave me a 3blink pressure switch stuck closed error and did not ignite the ignitor
Electric is currently removed from unit

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?

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.........


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-Brumfield-T7CS5D-12-PCB-Relays_W0QQitemZ250325856206QQcmdZViewItem

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!

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

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

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

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.

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

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.

Yep I figured that when the other guy said it blew up when he was using the 115 volt one. Lessons learned every day I guess.

Cool, glad you got it going. Also glad you verified it was a 220 his. Guess the manual for our machines is wrong. I thought so but have been working crazy hours and was unable to find out for hvac1000 yet. Good luck keep warm. P.S. my repair still works. :D