I have a Nordyne/Frigidaire G6RC furnace. The entire ignition sequence runs fine up until a signal is sent to the gas valve. It was immediately powering off with an error "False Flame or Gas Valve Relay Shorted" as soon as a 24v signal was sent, either to the gas valve or my cheap multi-meter. Now it just runs through several failed ignition sequences, giving me an error "Ignition Failure (Check Ground)." On each sequence it will spin up the draft inducer, produce a small click (I believe the HSI relay), light up the hot surface ignitor, produce a louder click (sounds like the gas valve is opening), then fail to provide a flame. I have verified that the board is sending 24v to the valve.

If I just connect 24v to the gas valve, I know some gas comes out, since I can smell it. Although, it's faint with a stuffy nose. I can't smell anything when the furnace is running through its cycle. It may be dissipating too quickly or not running long enough. I couldn't hear any sound of gas flowing over computer equipment in the basement, even with the valve wired directly.

A replacement circuit board had been installed by a technician who replace 4-6 furnace parts under home warranty. The replacement recently went out, and I still had the original part. With the original part, the flame didn't sound as robust as I thought it should, like maybe something was a little clogged, but I'm not qualified to diagnose furnace sounds. I didn't care too much about it either, since it was the first time using it this year. I was just happy to get some heat, but I think the house's temperature was a degree or two lower than it should have been by morning. The furnace was definitely not working the next night.

If it's just the circuit board, I can replace that myself without much problem, and save hundreds on a service call. If it's the gas valve, I'd rather not do anything wrong to it and blow up my house, especially while I'm standing at ground zero. Either way, I'd like to fix this quickly, since the weather changed overnight from highs around 70F to highs around freezing.

 

Welcome to the forum.

You had a technician there under the home warranty. Why is he not back there ?

You mention bypassing/powering the gas valve open but not be able to hear it over fan noise. If you're going to work on gas equipment like that..... shut down the noisy equipment and concentrate on the repair. Gas is not very forgiving.

If you are confirming that there IS 24vac on the gas valve and it isn't opening it.... then it sounds like it's defective.

 

The technician came here under home warranty 5 years ago, and it was a 1 year warranty. That's why he's not back (that, and it took him a cold week and 4-6 part changes to fix the furnace when he did come).

I can hear the gas valve open, or at least try to. I can hear the draft inducer, which is MUCH louder than the computer equipment. I can hear a relay or two on the circuit board. When everything worked, I could hear the gas flames. The only thing I can't hear is the flow of gas, and I don't even know if it should be audible. Given the relative volume of the draft inducer, the computer noise doesn't seem relevant enough to spend 30 minutes shutting everything down (which would include Internet access).

I can confirm that 24vac directly fed into the valve will open it enough for me to smell some gas. I can also confirm that the valve makes a noise like it is opening, both when the furnace is going through its startup cycle and when I wire power to it directly. I cannot confirm that it opens correctly in either case. If the voltage are finicky, the reading from my cheapest-Walmart-has-to-offer multi-meter could be off by a couple of volts.

Would a defective valve be able to trigger a "False Flame or Gas Valve Relay Shorted" error? That sounds more like its the circuit board. That's the only part that makes me think the circuit board could be the problem. This board was previously replaced by a possibly shady technician, but it also managed to start the furnace at least once before I went to sleep.

 

I called a technician (LBA Heroes in Kansas City). The furnace managed to actually worke when he showed up, but started failing again before he left. He said I needed a new circuit board that has to be special ordered for >$1,000, and that it would not work with a universal part. Nevermind that the Honeywell universal controller board (S9200U1000) that had run the furnace for 5 years was still on the floor next to the furnace while he said that, and it's a Honeywell gas valve that the board is failing to turn on. He also seemed to insinuate that there was a good chance the $140-$200 Nordyne controller boards I saw online were scams.

My old board does have some visible water damage, so I replaced it with the Honeywell board that worked fine before. The furnace ran just fine afterward, but only for a few minutes to a couple of hours. Same problems again. I wasn't home when he showed up, but I don't think he actually checked what the board was doing before calling it defective. He probably didn't have time after talking to my wife and convincing her that it would be worthwhile to go ahead and spend $4220 to replace the furnace and pointing out all the little things he would do a better job of when he installed it.

 

Here's a list of the Nordyne part numbers which can be replaced with the S9200U1000.

624591, 624557, 624564, 624628, 902378, 902696, 903106, 6245570, 6245640, 6246310, 624557-0, 624591A, 624591-A, 624591-B, 624591-C,624591-D, 624628-0, 624631-0, 624631A, 624631-A, 624631-B, 710128A, CAR903106

 

jbo5112, any update? Did you go ahead with ordering the new circuit board or did you find another solution to your problem? Curious...