johnceberhardt

P.S. my old carrier weathermaker hasn't failed at all. I think i'll go give it a hug.

Tiger81269

BAZZA,

What ended up being the solution?
My York just started doing the same thing a few weeks ago since turning it on and servicing the air filter. Since then it has worked a few times since I've been home (I travel a lot for work). But now that I've been home for a week it hasn't worked properly.
Thanks for the coming reply.

Dtodd

I am also having same intermittent problem with my York 15 year old York. Vent fan comes on, gas valve opens, spark igniter heats up, burners do not light all the way across, gas valve closes. Most of the time will stay lit on the 2nd cycle. If not, I have to turn off power. Works fine when power is turned back on. Heating contractor has changed control module, flame sensor, and burners.
Voltages are all good, vacuum & vacuum switches are good. Contractor now wants to change out the gas valve?? Any thoughts would be appreciated.

Tiger81269

My problem turned out to be a pluged water drain on the bottom half of the unit. Service Tech came and unbolted the lower electrical box, swung it out of the way to reveal a black box that a water tube ran into. It was full of water. He cleaned it out and removed the blockage. Furnace works great now.

Dtodd

Had already checked the water drain as well as the vent fan intake and exhaust pipe for obstructions. Also checked the heat exchanger for cracks. and checked for carbon monoxide in the vent pipe.
Service has now changed the gas valve as well but still having problem and are pretty much at a loss.
York tech support has not returned phone calls.

paul52446m

[QUOTE=Dtodd;52417]I am also having same intermittent problem with my York 15 year old York. Vent fan comes on, gas valve opens, spark igniter heats up, burners do not light all the way across, gas valve closes. Most of the time will stay lit on the 2nd cycle. If not, I have to turn off power. Works fine when power is turned back on. Heating contractor has changed control module, flame sensor, and burners.
Voltages are all good, vacuum & vacuum switches are good. Contractor now wants to change out the gas valve?? Any thoughts would be appreciated.[/Q
First of all you are saying it wrong, A spark igniter sparks to lite a pilot, a glow bar heats up and glow red to lit a pilot or main burner.
You are saying it wrong on the sequence for call for heat. First inducer fan
starts makes pressure switch, then after 15 to 30 seconds the glow bar is energized for 15 to 30 seconds and then about 6 seconds of gas valve.
now if it gets to gas valve and the gas valve does not stay open for that 6 seconds then all your burners might not lite. This problem can be a gas valve opening to slow, or the electronic board not giving you 6 seconds.
Another thing to check is make sure you are getting a full 24 volts to open that valve. Low volt ,like 22 volts makes for slow opening of gas valve
later paul

Dtodd

Thanks paul52446m.
The gas valve & the electronic board have both been changed out.
When it fails the gas valve stays open less than a second and the burner(s) nearest the flame sensor don't light.
I am getting 23.7 volts to the gas valve & 24.2 v at the transformer
I'm wondering if one of the vacuum switches is acting up.
HVAC contractor said he checked them but since they have now been here 5 times now I don't have much faith in them.
I have tried removing the vent fan intake pipe letting the furnace draw basement air thinking that if the vent fan was weak it would help, but that makes no difference.
The vent intake & exhaust are 5' longer than max recommended but it ran for 15 years with no issue. Thought about up sizing from 2" to 3" but now sure if that would help.
Will let you know when the problem gets solved.

paul52446m

You said something there that i don't like. Your 24 volt is getting low. Some co. use transformers that just large enough to do the job. A 24 volt
transformer should start out about 27 volts. This voltage can change by the amount of line volt power you have. Is your furnace on its own circuit?
Check the incoming power to the furnace. It should be at least 118 volts.
If it is not then go to you main electrical and test your mains. You are paying for 120 volts and when the voltage drops the amps go up and you pay more for your power. Depending on the power use in your area the voltage can go up and down. So leave a tester in one of your outlets and check it at different times. If you don't have at least 118volts, call your power co. and have them bump it up . That only takes a few min. they can adjust it at you transformer on the pole.
The lower the line volt power the lower your 24 volt power.
If your line volt power is up then you might have to get a larger 120/24 volt transformer.
Transformers have a VA rating on them. Lets say you have a 30VA transformer. To find out how much amperage that will handle you divide the voltage into the VA, so 30Va divided by 24 volts is 1.25 amps.
Now if your control are drawing 1.75 amps then you 24 volt power will drop too low. Doing service work i have called the power co. many times.
If you can't get the voltage up or you are drawing more amps then your transformer can handle then you would have to go to a larger VA rated transformer. I have seen people run phone wire for a thermostat and that drops 24 volt power real fast.. Later Paul

Dtodd

Paul,
Think you might be on to it.
I see my battery backup on computer had kicked on today although the furnace didn't completely fail.
I just read 26.7 volts at transformer with vent blower off, dropped to 25.8 with vent blower on and 24.8 with both furnace & vent blower on. Was reading 24 v at gas valve. My house voltage was 120.4 but I was only getting 94.4 volts at the fan limit once the vent fan kicks on, the blower fan did not drop the voltage any further. Getting 120.4 volts back at fan limit as soon as vent fan kicks off - and with the blower fan is still running.
Vent fan motor casing felt hot so I put a thermometer on it which read 120F with the motor running.
Beginning to suspect the motor could be the culprit.
I'll see if I can find an AC amp probe at work so I can get a reading on it.
Furnace is on isolated 20a circuit with only a light wall style switch between it and the fuse panel (at which I am getting 120.4 volts also). I will try bypassing the switch to see if that effects the voltage drop.
Thanks again for the help!
Dave

paul52446m

You might want to go to a larger VA transformer A larger Va will not drop the 24 volt as bad. A24 volt transformer feed with 120 volts usually starts out 27 volts. Can you see a Va rating on your transformer?
At the furnace check the 24volt going to your thermostat and then the power coming back from the stat. How much drop to you have there?
Later Paul