York Warm air furnace problems

BillAllen

Installed a York upflow furnace last year with AC coil. Furnace shutting down blowing cold air then on again normal then cold air. 4 flash error code says flow issue. I changed limit and temp control switches still a problem. Crazy can't figure it. All vents opened so a flow problem is puzzling me. Filter clean and new Ac coil seems ok.

Abracadabra

intake and exhaust vents are clear?
use manometer to verify. if below spec, vents or inducer are issue. could also be clogged ports on the combustion chamber. if in spec, replace pressure switch.

BillAllen

Yea but the 4 flash indicates vent issue. I supposed the pressure switch could be defective. The furnace is 5 months installed.

GW

Flow issue...can you type out the exact wording? You mean air flow? Did you check your temp rise?

BillAllen

1. When the heat comes up to temp, the supply duct stays warm. Not as hot as when blowing, but warm to the touch. It does not change to hold just because the heat turned off.
2. The cold air blowing through the vents seems to happen when it has NOT come up to temp. Example: left heat at 65, customer came home, turned it up to 68. It reaches 67 and then blows cold air.... and temp never gets higher. so I shut it off and on again and it is fine (once reset)

GW

Yes sounds like you have air flow issues, did you get a chance to stick a thermometer in the supply and return?

BillAllen

No I did not. All registers opened no clogged or blockages I can see or tell. Wondering if the pressure switch is bad. Furnace brand new. The flash code (4 flashes) indicates air flow issues but not sure what that could mean. Could the AC coil be an issues slowing down the heat from displacing? Customer had the coil there before the new furnace was installed. The heat was fine since the install and fine since the heat came on in November here in the northeast. More questions than answers, appreciate the discussion.

lchmb

Did you switch the blower to high speed?

BillAllen

York have that capability?

GW

Hard to say if you don't know the temp rise.

What size furnace was removed and what size furnace went in?

Was old furnace plastic or metal venting?

What about the new furnace?

Your filters are good?

Is the ac coil gooped with fur?

BillAllen

Same sizes, direct vent no chimney PVC, filters good, no fur.

GW

Ahh try bumping the fan speed up.

BillAllen

Never did it, swap wires at fan??

GW

At the controll board usually but maybe the blower motor, the manual should say or the board or blower should have some indication.

BillAllen

Ill check it out

BillAllen

Ironically now I have a W/M PEG steam Gas boiler I just installed. When I went to hit the switch the transformer fried. People without heat for the night need a new trans..first time ever wondering if there things are prone to this. Read on line such..

MilanD

@BillAllen

If the thing worked fine before and just started doing this and acting up, check the inducer condensate drain, trap, etc. for blockage. Not familiar with York, but I had this identical thing happen once on a Carrier. Fire goes on fine, then shuts off, cycles blower, restats burners and on again. It was the condensate not draining fast enough, this reduced the pressure at the inducer and switched it open, shutting off the burners. After a while, water slowly drains out and system refires.

BillAllen

Funny that I did not check I will though. Thanks for the reminder

GW

Bill get a popper fuse at the HVAC vendor and get a new trans.

Turn off power

Get new trans installed

Disconnect your stat wiring

Turn the power on

Trams still good?

Touch tour stat wire together. You should not kill the trans, unless someone at the factory wired it wrong, highly unlikely

Did you get your collector box (back of boiler) roll out switch wires attached to the switch?

If the boiler fires then get your popper fuse on one leg of the stat. Try to fire with stat. Did the popper blow? If yes you wired something wrong.

Hope you get your customers heated up ASAP

BillAllen

Thanks I'm getting the Trans/relay at the supplier tomorrow. Everything wired correctly. One black one white from switch to Trans...simple do them all the time. When I took off the transformer it was black and fried bad smell. Had 110V from switch to trans switched it on and it just blew, crazy. This is the W/M PEG50 Steam gas very simple wiring but yet it blew.

MilanD

> @BillAllen said:
> Funny that I did not check I will though. Thanks for the reminder

Yeah, had me there for a moment too. And code also showed air flow resteiction, as in, blocked pvc vent/intake air flow, then pressure switch fail to close (2 codes). I check it, all clean. Check switch, works fine. After a minute, all comes back on. Then shuts off again. Gurgling sound at inducer, so I take off drain hose, water pouring out. Side condensate trap almost completely stopped up... Cleaned it off, no issues.

For good measure, if this doesn't fix it, there might be a broken off inducer fan blade... It would not spin consistently at the shaft (motor would spin, but fan blade inside the housing would be detached), and it would have same issue - code would show restricted air flow.

BillAllen

Turns out we wired the transformer with 2 hots! We didn't know that the white wire (Neutral) was actually hot! Fried the transformer and the LWCO. I had to eat some of these controls.

BillAllen

Back to my York warm air furnace. Well I took off the filter and the unit ran for quite a while with no flash codes. I also enlarged the return air at the furnace but I am still getting 4 flash codes but with heat. Comes up to temp heats the house but near the end of the cycle the flash codes present and the burner will shut but come on again without reset. So there is heat delivery but still premature shut down. I notice the ducts are huge in the attic probably 20" in places. Wondering if heat cannot circulate properly due to return size or if increasing blower speed would help the situation.

GW

Yes the temp rise tells you all that. I'm guessing you don't do static pressure readings, that tells a story too. You need some more tools, things are happier when you can find what's up with furnace issues.

BillAllen

No I install these things for years never did a test on one of them except gas pressure testing. Still might be the inducer switch could be overheating there.

GW

Yes but pulling an air filter and seeing it run better has nothing to do with a draft inducer or its related pressure switch.

BillAllen

O I know that. Even with the air filter off after some time the shut down still occurred. I'll be bringing in York Tech repr with me next week to assist. I might even try increasing fan speed. I believe it is running on mid/high right now.

BillAllen

I do have the UEI EM201 Manometer for static pressure testing.
I have field Thermometers as well. Next week I will conduct the static testing.

BillAllen

Problem back after increasing fan speed. 4 amber flashes. Pain in the **** these furnaces are!

GW

Did you check the temp rise and the static pressure? Filter good?

lchmb

are you sure something hasnt plugged the inlet to the coil?

upnyhvac

What's them model of the furnace? Their mod will show that code if there is a temp rise issue.

BillAllen

TG9S080B12MP11 York. Works for a while then blows cold air. Off on high limit I suspect. Filter good Customer a fanatic changes it quite often. Didn't check the coil. Doing the static check this week.
Changed the board, limit switch, roll out, enlarged return opening, Changed speed to high (Black wire). Duct work looks fine. All vents opened. Can't seem to move heat fast enough for the the limit.

GW

80,000 btu? What size ducts? What size filter?

Tinman

Its probably been said, Bill, but my first suggestion would be to stop changing parts. As Gary mentioned, you have to check the temperature rise across the furnace. The acceptable range is printed on the furnace's data plate. That's the starting point whenever a furnace is bumping limit.

Harvey Ramer

If I am correct, the York, or any other Johnson controls product, will turn off every function except the fan when the high limit trips.

Quite a few people have asked you to check your temperature rise across the furnace. I would do the same.

BillAllen

I believe the duct sizes in the attic are -12-16" round most of them. Tech coming out. Static test.

BillAllen

Filter 201X16 80,000BTU removed 80,000BTU replaced.

BillAllen

Tech and I figured it out. Supply Temp 171 return 72. Adjusted gas pressure too high. Lower speed. Will cut in another return if needed. Furnace was a little oversized that was the problem. Some vents were also closed.

Tim McElwain

If you adjusted the gas pressure you need to do a combustion analysis to be safe.

BillAllen

Yes