Hi All...

Hopefully uou can help me out...

I have a york diamond 80 gas furnace. It was working fine up until a few days ago..
It began to blow out cold air when the house clearly was not even close to "requested" temp.

It turns on, starts the initial motor, the humidifer also kicks on, the igniter glows, gas ignigts, after a few, the blowers kick on, glow on the ignighter dies down, unit runs beautifully for a bit... Flames goes out instantly (they do not go out gradually)... Some times it runs for 2 minutes, sometimes 5, sometimes 15.. Seems like no ryme or reason.

My brother in law is a "tin knocker" soooo he knows a few things about these things. So he came over looked and so far has replaced the board, and limit controller.

Still doing the same thing..

I feel bad calling someone else in, but If I can just offer him some suggestions that he hasn't thought of.


:eek:

Frozen in NY,
Me

Tin knockers are not necessarily service techs. If he is just randomly changing out parts then he obviously has no clue what he is doing and I'm sure he knows that... probably just doesn't want to admit it. Call in a local service company as it could be one of several different problems all of which would be difficult to help you with having to go through a 3rd party.

Tin knockers are not necessarily service techs. If he is just randomly changing out parts then he obviously has no clue what he is doing and I'm sure he knows that....probably just doesn't want to admit it. Call in a local service company as it could be one of several different problems all of which would be difficult to help you with having to go through a 3rd party.


Thanks Mark,

I appreciate your fast response. I know he is a tinknocker, but honestly, I wouldn't let him screw with it, if I didn't have faith in him (last thing I need is my house to become the New years fireworks show! )

So far from everything I have read, it doesn't seem like he is randomly changing parts. The board was replaced because things were kicking on and off out of sequence, and the limiter was the next seemingly logical thing.

From what I know and have read (again, complete amiture DIYer) it seems as if all the actual parts are working as they should be... (I forgot to mention too, that he cleaned the flame sensor) Im wondering if is a safety somewhere in the unit. However, there is no fault codes that would indicate that according to the board.

Also, FIY, last night I had the therm. Set to 80, and it ran for what I believe to be all night, with both hot and cold cycles (fan continuiously running) and only reached 60 degrees.
(It wasn't the tropics, but thank god it was the artic either! )

Any insight would be helpful!

Again I say that tin smiths are NOT service techs. Believe it or not they are 2 different but somewhat related trades. Tin knockers have their own apprenticeship that they go through and it doesn't involve troubleshooting a system. If he is changing out parts and the system s still not functioning properly then he is what we call a 'parts changer'. He may get lucky and eventually change the correct part but chances are that it will most likely cost you more than it would to call out an actual service tech. Residential systems are, for the most part, as simple as they come and most of the regular posters on here could more than likely have this figured out in less than an hour. My point is that your brother in law does not sound like he knows what he is doing, no offense intended. Save yourself a lot of down time and call in a reputable service company. If you had faith in his ability then you wouldn't be on here asking us. That is my advise to you, whether you choose to listen is entirely your decision.

Again I say that tin smiths are NOT service techs. Believe it or not they are 2 different but somewhat related trades. Tin knockers have their own apprenticeship that they go through and it doesn't involve troubleshooting a system. If he is changing out parts and the system s still not functioning properly then he is what we call a 'parts changer'. He may get lucky and eventually change the correct part but chances are that it will most likely cost you more than it would to call out an actual service tech. Residential systems are, for the most part, as simple as they come and most of the regular posters on here could more than likely have this figured out in less than an hour. My point is that your brother in law does not sound like he knows what he is doing, no offense intended. Save yourself a lot of down time and call in a reputable service company. If you had faith in his ability then you wouldn't be on here asking us. That is my advise to you, whether you choose to listen is entirely your decision.

Thanks Again..

No offense taken at all, all though, I do say it didn't answer my question at all. Your advice was, well informitive in the diffrences between the trades, but not really helpful to the actual problem.

I did have a service guy out, and well.. No luck.. Paid a hefty ticket for him to suggest changing the board.. (not knowing we just had) and to stand there scratching his as... Uhh I mean, head.

He said there is no fault code showing (funny, the finance person that I am, knew that) and everything seems to be working properly, so he doesn't understand why it would run cold... He recommended changing the therm. Next. Oddly enough, perhaps he is a tin-knocker acting as a service guy, cause this is the next thing my bro-in-law suggested changing.

I did read somewhere that the vent pipe (which leads out to the roof) could cause this if the outside air blows into the pipe... The persons post was really not well written and didn't seem right, but I figured from the responses that I have read on this board, you guys seem to know a good deal about the little oddities that furnaces have.. So have you ever heard about that?

Anyway, if anyone other then Mark has a suggestion for the actual physical problem, I'd love to hear it.. But Im well versed in the diffences between tin knockers, HVAC guys, electritiions, teamsters, laborers, etc (grew up in a variong union family)

Thanks Again,
Happy new year to all!

You may have a faulty transformer (not consistently powering control system). Most modern furnace controls will cause continuous blower operation if control power is lost. This occurs more commonly if the high-limit opens, but the same will result from most any loss of control power to board. Check electrical connections to all safety devices, particularly any that appear to have been exposed to moisture. Internal oxidation of switches, etc. can cause intermittent circuit failure, or allow partial voltage that keeps circuit board in "limbo", unable to recognize and diagnose faults. It is rare, and thus overlooked or undetected by many techs.

Thanks KC, I'll/We'll check that out!!

I picked up a new digital programmable therm today. So we are going to be putting that in as well.

Funny, last night it went through about 3 cycles working perfectly.. I was all excited, thinking some how, some way, the god of heating had taken pity on me...
Well, this morning, someone must have pee'd in the Gods wheeties, cause Im back to hot,cold,hot, cold... Errrrrgggghhhh!

I'll keep you'll updated! Thanks again for your help!

Melissa

I'll keep you'll updated! Thanks again for your help!!

Melissa

Hey Mel, I have the same furnace and same problem this week.

Mine was flashing an error code on the front diagnostic window that was 8 flashes. This indicates the flame sensor being dirty or defective. Either way, non-operational.

I spoke with a local York rep who's also a refrigeration mechanic etc. years in HVAC. He said yes, it's the flame sensor. But could also be the igniter. He recommended replacing both which is an easy process requiring only a philips screwdriver. Cost me $70.

You can clean them if you're extremely careful. This may fix the issue but perhaps not, if they look clean already. I opted to replace them to get the problem fixed asap with the highest degree of safety.

You can remove the upper front cover which will give you easy access to the two parts. One is on the right, the other the left, just over the burner. Your relative who's been helping you should know what's what here on this. Took me 2 min. to replace them both.

Hope this helps. I had a company come by three times to try and fix the furnace and were scheduled for today as well. Cancelled this last call and will be asking for a partial refund.

Ps. MarkwithaK is right. Beware the parts mechanic.

I have the same problem. After the furnace starts blowing cold air, I turn it off. I take off the top and bottom cover of the furnace. The bottom cover has a reset swtch when I put the cover back on. I turn the furnace on again at the termostat. After a few minutes the burners light and the we get hot air again. After about 10 minutes the blower blows cool air again. A reputable tech said that the blower motor was overheating and tripping the limit switch which turned off the burners. He said that the blower motor needed to be replaced -about $650

Having similar, if not the same, problem as described above. We set the thermostat to, say, 70 deg. The furnace will kick on and heat to that temp. The burners will turn off but the blower stays on and pumps cold air, so much so that the temp drops to 65 or so at which point the system (burners) kick back on and the vicious cycle begins. We are also getting the 8 blinks on the m-board LED. We have had a tech out 2 times. First trip, he cleaned the flame sensor. Second trip, he replaced the flame sensor. We've also installed a digital/programmable t-stat and are now reaching the "fed-up" point with this. Do we now replace the motherboard or investigate further the blower motor theory?

Just to piggy back on my above post. I forgot to add that once the temp drops to 65, the system kicks off, then immediately kicks back on to warm it back up.

I has totally forgotten about this post... After that particularly bad winter, we finally figured out what the problem was... Someone had moved a dresser in front of a return vent... The system was starving for air and ultimately running too hot.
Dresser moved... Problem solved.

This question was asked over 3 years ago! Hopefully it is fixed by now