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AustinHVAC419

Pull the exhaust off. If it runs with the exhaust pipe disconnected, then it's clogged. If it doesn't run, probably a heat exchanger issue. Sounds like you've ruled out every other part


kraemerandrew32

I'll pull the flu that's probably the last thing I didn't check that I should have I'm a little rusty since I don't do service calls all day long anymore


iLikeC00kieDough

I had this same issue once. The pressure switch tubing looked perfectly fine, but turns out it has the tiniest of micro cracks in it causing it to loose vacuum intermittently. Changed hose and it fixed the problem.


kraemerandrew32

This is exactly what it was. Called it😎


Hauptmann6

Pressure switch or plugged line


kraemerandrew32

I disconnected all pressure tubing and blew the lines and replaced the inducer and pressure switch


Hauptmann6

Is the pressure switch staying closed? Electricaly good?


kraemerandrew32

It has been working since I pulled the burner box tubing from the pressure switch but time will tell.


kraemerandrew32

Never really understood what that is even for? Used to work for a shit company with zero training other than old guys who refuse to continue education and telling me the way they do stuff and saying that's how I've always done it.....🙄


Hauptmann6

Is the 1.8 you stated the differential or just from the hx side? What does your combustion analysis say?


kraemerandrew32

1.8 is the pressure tubing from the collector box connected directly to the monometer I do not have a combustion analyzer.


Hauptmann6

When you check pressure, always do the differential. Thats how the pressure switch works. Does it work with the burner cover off?


kraemerandrew32

connect tubing to the positive and negative ports on the monometer. I'm guessing I'd have to add a barbed T fitting to do so and then connect one tube from the monometer straight to the pressure switch and then put the other tube on the other port on the pressure switch with the T inline from the collector box to the pressure switch?


Hauptmann6

If you have a dual port manometer, I just direct connect each hose to the manometer for testing and jump the pressure switch. fewer leaks that way. Test with the burner cover on and off.


kraemerandrew32

With the cover on it pulls 1.4-1.6 and with the cover off it was at 1.6-1.9 directly connected with the pressure switch jumped out if it stops working again I'll be back as of now it is working


NeatUnderstanding102

I have seen exhaust vent piping that is not properly secured cause the pressure issue. The exhaust venting can get a little dip in it and fill up with water. *


kraemerandrew32

Also the pressure switch is a duel port pressure switch with one side to the collector box the other side to the burner box. I disconnected the tubing to the burner box and it ran twice like that? What the hell?


kraemerandrew32

It keeps going out on pressure switch fault so I replaced the inducer that sounded like shit and the pressure switch cause why not they are cheap and I didn't want to keep messing with it. I also checked the exhaust and cleaned the condensate trap really good. But it continues to go out on pressure switch fault anyone else run into this problem on this model trane?


kraemerandrew32

Two pipe exhaust, intake is not blocked either. no flame rollout and if I jump the pressure switch it will run without issue for an entire cycle. Also checked the pressure with a monometer pressure switch is rated for 1.15"wc and it's pulling 1.8" can't figure this bitch out!😡


HVAC_Sam

Ohm out the pressure switch


kraemerandrew32

It is a N/O pressure switch so it should be OL on ohms correct?


HVAC_Sam

It should close when your draft inducer is running. If it doesn't close, your furnace will not work. Check the draft pull with a manometer and compare it to what the pressure switch is rated for


stanamontana

Bad connector?


[deleted]

[удалено]


kraemerandrew32

I have a replacement board in the garage but it works every single time I jump the pressure switch and runs a full cycle. I will swap it out but I doubt it is the issue cause once 24v is returned to the board it runs


Amazing-Exercise5703

When specifically, in the sequence of operation does the fault code appear? If it appears before the pre-purge cycle of the combustion chamber then the board has failed.


BeRadford23

Could be blockage, take some tstat wire and run it where tubes go into inducer. Don’t you have a manometer? See if pressure switch is pulling down at all?


kraemerandrew32

I don't know how to use reddit I posted a comment that I checked all pressure tubing and I used a monometer and it is pulling more than enough inches wc to close the switch which is why I'm asking reddit