HVAC help needed.

[ez bake]

So my heater comes on just fine (Frigidaire G6R - don't know if it's an A, C or D right now as I just put the cover back on), but it cycles normally and won't come back on (flashing red light on circuit board - 4 times). I can turn off the thermostat and then turn it back on and the heater cycles just fine until the next time. Every now and then, it will work on it's own that second time.

Found the manual for it here:

http://www.transtaracsupply.com/pdf/g6_service.pdf

So I'm confused, 4-flashes indicates a soft-lock in one part of the manual, while it also lists it as an "ignition failure (check ground)".

Could it be that my coil-igniter is close to burning out (and is reading low voltage on the back side of it) and it's causing it cycle normally and then prevents it from running again?

I'm no Heating / Air expert, but I'm generally pretty handy with fixing this stuff (cleaned off the flame sensor last year with some sandpaper and saved us a cold holiday night since no one wanted to come out for a service call).

Any input is appreciated.

 

[tyromeo55]

My first thought is to start by sanding the flame sensor again. Are you sure it is cutting the flame ( when it does run ) because the thermostat is satisfied?

 

[ez bake]

My first thought is to start by sanding the flame sensor again. Are you sure it is cutting the flame ( when it does run ) because the thermostat is satisfied?

Definitely running until it's supposed to stop - it gets to 1 degree above what the thermostat is set to and kills it (normal behavior based on what it's done in the past). According to the book, continuous flashing yellow light is flame sensor.

I just watched the ignition coil get to a light glow and shut down without engaging the gas jets. The gas-vent blower kept going and it tried again and worked this time.

At this point I'm 99% sure it's the ignition coil (I picked up one right before Locke closed today just in case that was the issue). I really don't want to have to get up every few minutes tonight to adjust the thermostat (or worse, it stops working altogether).

 

[tyromeo55]

It could be the hot surface ignitor but doesn't really sound like one. You can test the one you have if you have a clampmeter. As it comes up to temp it will pull more and more current. Fully on it should be like 3.25 to 4.5 amps if I remember that number right. Some boards look for it to reach a certain current to initiate the gas Generally that kind of board does not time out. Still, It does not sound like your problem and generally HSN's in furnaces usually just burn out and not get weak.

You say that you cycle the thermostat off and on and it comes back on. That would not reset the board, When a gas furnace calls for heat it connects the red and white terminals together ( make sure your installer did not swap colors ) and when it is satasfied it opens them ( your fan should continue to run until the board on the unit is timed out) resetting the thermostat would not do any more then what it should be doing normally. Do you have a digital thermostat? if so how old is it? Have you tried new batteries?

 

[bettingpython]

Flame sensor is going likely going bad, when heated disimiliar alloys (thermocouples) generate a few miilivolts of current that gets read by the board if the current drops off then the board shuts down the gas valve. Hot surface igniter would not cause the cycle to abort. Also Make sure your pressure switch tube is clear if you have an induced draft furnace. I would try replacing the flame sensor(sanding the exterior of a thermocouple really doesn't do anything) and maybe the pressure switch. Then you have the board or a weak gas valve solenoid as possible culprits both of which get expensive fast. Good luk.

 

[ez bake]

I now regret not buying a clamp for my multimeter last year when I saw some Fluke goodies on sale.

Well - so it started to cycle one more time and didn't ignite at all - igniter started glowing and went back to cool (gas jets didn't even attempt to fire). Vent blower stayed on and it tried again and didn't even get very bright and went back down. It clicked again and sounded like it was attempting again (I don't know how many times it's supposed to keep doing this) and didn't do much of anything and then shut off. 4 blinking red lights again. Cycling thermostat does nothing now.

Previously to this point, it has cycled normally at least one full time (complete cycle - I upped the thermostat 5 degrees to see - it got all the way to one degree above what I set - didn't shut down early) and then it doesn't attempt to do anything (no click from the thermostat, no igniter starting, no gas from the jets - nothing... I just watch the temp decrease on the thermostat). I've replaced batteries (cheap digital thermostat) and reset it multiple times earlier today.

The guy I bought the part from also said that he couldn't see why recycling the thermostat would make it work other than in some units, a soft lock only lasts so long and it will try again in a set amount of time (and by cycling the thermostat, I was effectively fooling it into thinking that a set amount of time had passed), but that he didn't know much about Frigidaire heaters. I told him that neither did I and I needed the igniter just in case it goes out on me tonight.

So I replaced the igniter and it fired right up and has cycled 3 times now with no issues. I'm still holding my breath though (we're having drain issues too - great day so far). I'm hoping my hot-water heater isn't what completes the "bad crap comes in threes" thing.

Appreciate the help though - I got pretty nervous when it was acting weird and didn't seem like any one thing was wrong.

 

[bettingpython]

Glad to hear it worked. We got home from NOLA and our house was cold the hot surface igniter went out, then I picked up a stomach bacteria, most likely from the nasty water at the truck stop in shreveport we stopped at on the way home. In the middle of that our sewer line backed up new years day. So far my bad luck stopped at 2 hope the same holds out for you.

 

[tyromeo55]

Good deal, If it does start cycling odd again, Id short the thermostat wires R and W and see if it comes on after some time I'd take them apart and wait for the fan to come off then put them back together. If it works that way then your going to need an new stat

 

[ez bake]

Well crap - it cycled fine for about 7 or 8 times and then I just walked past it and saw that the thermostat showed 67 degrees and it is set to 71. Looked on the board and I have a red light blinking 4 times again.

Turned thermostat to off and back to on and heat comes on and heats up to 72 degrees (one degree above the 71 I had it set to) and then kicks off normally. No blinking red light this time. Just a constant red light (which is normal according to the service manual). I watched it from when it finished the cycle until the temp got below what the thermostat was set to and it kicked back on and cycled normally again. Once it finished the cycle, solid red light again. It seems to be cycling normally now (at least through two cycles).


A blinking red status light (4 times) means soft lock out from what I can tell, and it will try again every hour?

According to the manual's troubleshooting guide, a blinking red light 4 times means: "Ignition Failure (Check Ground)" but I've got a new Igniter (and I just saw the old one slowly fail, or so it appeared). Not sure which ground it is referring to, but I'm getting tired enough that I'm breaking out the space heaters and electric blankes just in case and heading to bed.

It really seems to me like a thermostat error. Once it cycles normally, the thermostat (when the heater is off) doesn't click or anything when the temp goes below the set temp - but it only does this if the light on the circuit board is blinking 4 times - which means that the system is in "soft lock out"?.. so it would be preventing the thermostat from even clicking (which is, I assume closing R to W)? That's the thing that stumps me - the occasional blinking (red 4 times) light on the circuit board shouldn't happen if it was a thermostat problem, but would it prevent the Thermostat from actuating?

Thermostat is a Hunter 42999B (cheapie Digital). I just changed the batteries in it and reset it again (wasn't sure if the other set of batteries I used when changing were good or not, but the thermostat does have a low-bat indicator and it didn't show up).

 

[HMFIC]

Hope you get it going. I think the flame sensor is a dead issue at this point since it's not even trying to ignite. If that were it, you'd get flame and it would just shut down after a few seconds for no apparant reason and then try again.

I had an issue once when we lived up in NH where the intake for fresh air was blocked by ice and snow and somehow there was a sensor that detected that incoming airflow restriction and shut everything down... maybe with the cold and snow we've had something like that is going on? Mine was because there was a screen over the intake outside that got iced over.

Anyway, I don't know too much about it but maybe that helps?