[123pugsy]

My York, TM9V080C16MP11 is flashing a red code 6.
Google tells me modulating gas valve needs replaced.
Anyone know of any other faults that may occur before I throw parts at it?

Also, is it a simple install? (For someone good with tools that is)

Thanks,

 

[beenthere]

Considering that your furnace isn't a modulating furnace. Save yourself some money. Your pressure switch is opening several times(4 or 5, depending on which control board it has) while in a heat call.

 

[123pugsy]

Considering that your furnace isn't a modulating furnace. Save yourself some money. Your pressure switch is opening several times(4 or 5, depending on which control board it has) while in a heat call.

Thanks.
Pressure switch defective?
Control board?

Edit: Problem with my googleator. Looking at the wrong furnace model codes, DOH!

 

[123pugsy]

I found what you were referring to:

6 RED FLASHES: This indicates that after the unit was operating, the pressure switch opened 4 times during the call for heat. If the main blower is in a “Delay on” mode it will complete it, and any subsequent delay off period. The furnace will lock out for one hour and then restart.

So, what needs to be done then? Wait to see if it starts working again?

 

[beenthere]

Could be a flue or air intake problem. Or worse, a heat exchanger problem. Also a good chance moisture is in one of the hoses, or in the pressure switch. could be a defective switch also.

 

[123pugsy]

Could be a flue or air intake problem. Or worse, a heat exchanger problem. Also a good chance moisture is in one of the hoses, or in the pressure switch. could be a defective switch also.

I've been warned about the heat exchanger running it in cool basement during my construction. Could it get toasted in two months of abuse?

Any diagnostic tips?
Flue and intake are clear. Brand new pipes with screens.

 

[beenthere]

Possible. But very unlikely.

 

[yuri]

Check the hoses that attach to the switch for moisture. Take them off one at a time and blow them out. Check the port they attach to for blockage. Poke it thru with a drill bit or nail.

If it still acts up replace the switch OR you can buy a differential 2 port manometer and check the vacuum while running. If it is close to the tripping point you may have a real problem.

 

[user_12345a]

I've been warned about the heat exchanger running it in cool basement during my construction. Could it get toasted in two months of abuse?

Any diagnostic tips?
Flue and intake are clear. Brand new pipes with screens.

Check the condensate trap and drain piping.

Undo the hoses between the pressure switches, burner box, inducer etc and blow through them; could be blocked.

 

[roughneck]

Is this unit really only 2 months old? Why not call the install back and let them fix it?

 

[123pugsy]

Check the condensate trap and drain piping.

Undo the hoses between the pressure switches, burner box, inducer etc and blow through them; could be blocked.

Hoses clear from blowing.
There may be a slight gurgle where one hoses goes into a plastic fan housing?

 

[123pugsy]

Is this unit really only 2 months old? Why not call the install back and let them fix it?

Nope. Not two months old. About 4 years. Been abusing it for two months with a lower than recommended air return temp supplying the unit.
(house is not insulated yet)

 

[roughneck]

If that's the case, the unit is probably loaded with moisture.

 

[yuri]

Overheating it will cause the exchanger to fail. If it was oversized for the other house and cycling on the limit or running too hot then yeah it may be damaged.

Sounds a bit suspicious. Usually the switch proves at startup and does not drop out. If the exchanger is cracked and expands after running 5 or more minutes then it could trip. Very rare that condition happens where it trips mid cycle.

Make sure the furnace is sloped forward about 1/2 to 1" from back to front so the condensate flows faster. With it running cooler it may be producing more condensate and backing up in the secondary heat exchanger or it is just not flowing fast enough and adding slope helps.

 

[123pugsy]

It's running for about 5 minutes and then stopping when it does start up again.
I can kill the power and restart and it runs for a bit and dies again.

 

[user_12345a]

Does the fan keep on running before the cycle starts again? I'm thinking it could be the high limit tripping. Check the schematic on the blower access panel for codes - there could be more than one revision of the tm9v, slightly different boards etc.

If you have a direct relationship with the hvac sub that did a lot of work, maybe call, may do you a favour and not charge much.

To check the pressure switches a manometer would be required.

This is a two stage funace - it's also possible that it's set up to hit high fire after 5 minutes; high fire uses a second pressure switch to verify draft, it will lock out if the second switch doesn't close when it goes in to high speed.

 

[yuri]

It's running for about 5 minutes and then stopping when it does start up again.
I can kill the power and restart and it runs for a bit and dies again.

Sounds like it is not draining the water out fast enough or producing too much water.

Check the temp rise and slow down the fan to get it within spec and it should not overproduce.

Make sure it is draining out of the trap at a good steady trickle. If I remember you put some corrugated drain line to your floor drain? If it is not draining fast enough thru that line it can back up. Remove that line and drain it into a bucket and run it for 15 mins and see if it stops. If it doesn't then you got a flow problem or dirty trap.

 

[user_12345a]

Has something changed? temp setting? Anything else?

The 95%+ furnace will produce lots of condensate; can't see it producing so much condensate it doesn't drain off.

With variable speed blower temp rise should be okay at factory setting.

something's up especially if it's been running the same way before.

None of us, even the techs with experience can figure what's happening without physically being there or giving step by step instructions going back and forth -> check this, check that, etc.

 

[beenthere]

New pipes with screens? Have you gone out and looked to make sure nothing is restricting those screens. Any sags in the new pipes?

 

[123pugsy]

Sounds like it is not draining the water out fast enough or producing too much water.

Check the temp rise and slow down the fan to get it within spec and it should not overproduce.

Make sure it is draining out of the trap at a good steady trickle. If I remember you put some corrugated drain line to your floor drain? If it is not draining fast enough thru that line it can back up. Remove that line and drain it into a bucket and run it for 15 mins and see if it stops. If it doesn't then you got a flow problem or dirty trap.

Temporary drain hose disconnected and same thing. Haven't hooked up to the permanent drain line yet.
Water drips out onto the floor with the hose disconnected.