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carnix · Mar 28, 2009, 01:12 PM

I have a Nordyne HVAC, Model C3BA-060C0C. I noticed that the fan would kick on and off continuously, regardless of thermostat settings -- that is, no heat or AC request.

On further inspection, the red control LED is displaying continuously, indicating "False Flame or Gas Valve Relay Shorted" I've watched the ignitor function, it glows extremely brightly and the actual heating process functions correctly, although the red LED continues to remain continuously on.

I've read similar responses to this question on this site and others and I inspected the 3 amp fuse on the control board -- it's the only fuse I could find -- and it was intact. I can hear some clearly audible clicks when the fan kicks on and off from (I think) behind the circuit board, and several such clicks when the system kicks in gear when an actual heat request comes from the thermostat.

I read hvac1000's answer on this thread , but I'm not sure I fully understand the process he's describing. I have a fair level of technical saavy in these areas, but I sure don't feel like blowing up my house by screwing around with the gas valve... so I'd love some more details and advice.

Thanks!

carnix · Mar 28, 2009, 01:18 PM

Originally Posted by carnix

I have a Nordyne HVAC, Model C3BA-060C0C. I noticed that the fan would kick on and off continously, regardless of thermostat settings -- that is, no heat or AC request.

On further inspection, the red control LED is displaying continuously, indicating "False Flame or Gas Valve Relay Shorted" I've watched the ignitor function, it glows extremely brightly and the actual heating process functions correctly, although the red LED continues to remain continuously on.

I've read similiar responses to this question on this site and others and I inspected the 3 amp fuse on the control board -- it's the only fuse I could find -- and it was intact. I can hear some clearly audible clicks when the fan kicks on and off from (I think) behind the circuit board, and several such clicks when the system kicks in gear when an actual heat request comes from the thermostat.

I read hvac1000's answer on this thread , but I'm not sure I fully understand the process he's describing. I have a fair level of technical saavy in these areas, but I sure don't feel like blowing up my house by screwing around with the gas valve... so I'd love some more details and advice.

Thanks!

One thing I'd like to add: I have a meter and I know how to use it, but again, before I go pulling parts off the gas valve, I'd really appreciate some more specific advice on how I should go about testing it for a short. Thanks!

Joshdta · Apr 3, 2009, 03:39 PM

If it light and heats then there should be nothing wrong with the gas valve. If you fan is short cycling. Then it is either a limit switch or the control board its self.

carnix · Apr 4, 2009, 04:42 PM

Originally Posted by Joshdta

if it light and heats then there should be nothing wrong with the gas valve. If you fan is short cycling. Then it is either a limit switch or the control board its self.

Yeah, actually, yesterday a neighbor of mine, who is a commercial cooling engineer or whatever (I guess that's the equivalent of large-scale HVAC, but since all the commercial guys tend to loath residential HVAC they came up with a more interesting name... heh), came over a took a look (saving me a boat load of money) and told me basically same. Actually, he told my wife the same since I wasn't there at the time, but from what she told me he said, it was the control board and some sort of switch (the clicking sound). He's going to get all the parts for us wholesale for cheap and install them no charge -- even give us a new thermostat because he thinks the one we have is a POS. Anyway, probably saved us several hundred bucks. He said if we hadn't noticed, eventually the fan motor would have burnt out, and that's an expensive fix.

Nice to have friends like that ;)