Finding correct pressure switch for York furnace

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Old 10-21-11, 01:58 AM
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Question Finding correct pressure switch for York furnace

Hello all, first post here.

My furnace has not been working so far this year and I believe the problem to be the pressure switch. I want to replace it but I can't find any part number on it.

I've identified several switches online that I can order which appear the same, but they each have different ratings such as 0.17" W/C. I don't know what rating switch I need as a replacement and I've been unable to find a parts listing for my furnace.

It's a York furnace of model number GM9S060B12UP11H

Can someone direct me to where I could find the proper rating or part number for a replacement switch?

Thanks!
 

Last edited by gkimsey; 10-21-11 at 01:58 AM. Reason: Typo
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Old 10-21-11, 05:19 AM
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rarely is the pressure switch at fault!

All I did was put your model number in google and found a parts breakdown with part number and I also found a switch. Did you even try?

http://luxaire.com/PDFFiles/035-20710-001-A-0205.pdf

FYI : Luxaire is the same as york
 
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Old 10-21-11, 10:52 AM
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When a furnace doesn't operate because the pressure switch stays open, the actual problem is the pressure switch about 2% of the time.

The correct way to check the operation of a pressure switch is with a manometer, measuring the pressure being applied to it and comparing it with the rated pressure at which it closes.

If you haven't done that, don't start by replacing the pressure switch. You are very likely wasting time and money.
 
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Old 10-22-11, 01:55 AM
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I must've mistyped the model number when I tried before, because I didn't get anything back by Googling it. Sure enough, pasting what I have here gives the PDF you linked with the part number I need -- thanks.

Regarding the pressure switch being the problem, I have my doubts on that too. I had a technician come out to check on it, he determined it was the pressure switch, but the cost to have them replace it was too high for me so I decided to try to do it myself. (2 tubes and a few wires -- how hard can it be? Famous last words).

Anyway, I'm not sure the guy really knew what he was doing. He/we checked the exhaust and intake. He disconnected the intake pipe near the furnace box and the pressure switch open error cleared, so I thought, okay, intake must be obstructed, but I/we checked it and didn't find anything. The exhaust had a dirt dauber nest in it that probably restricted some air flow, but while I'm no expert on fluid mechanics it doesn't seem like shortening the intake pipe a bit would make the difference if exhaust is what was blocked. Regardless, I cleared that out and the error code remains.

Long story short, I think the pressure switch technically could still be the problem, but the symptoms don't conclusively point at it. I have no other ideas that don't involve calling the HVAC guys back and saying "I didn't try replacing the pressure switch because yours cost too much but I think your guy was an idiot."

Since the switches run $30-40 online, I guess it's worth the risk to try it versus dropping another $100+ on bringing a tech out again. And obviously I don't have a manometer.
 
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Old 10-22-11, 02:12 AM
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Actually, that's a $1500 part since you'd have to replace 50 of them before replacing one that was actually bad.

But spend the money and wait for days before finding the actual problem.
 
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Old 10-22-11, 08:04 AM
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Ensure the condensate trap is clear and clean.
 
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Old 10-22-11, 11:29 AM
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I removed the condensate trap and checked it. Ran some water through it and didn't notice that anything had collected. Water flowed normally. Reconnected it and I still have the pressure switch open error code.
 
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Old 10-22-11, 12:45 PM
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You need to inspect the entire venting system and heat exchanger for anything plugged up or impeding air flow.

I fairly common problem is rust and debris plugging the port on the inducer housing that the rubber tubing connects to. A leaf being pulled into the air intake or water not draining out of the furnace caused by sagging piping can cause a water trap that will impeded air flow.

You have to inspect the entire system with care.
 
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Old 10-23-11, 06:13 AM
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The aforementioned dirt dauber nest was in the intake pipe, not the exhaust as I had thought. Likewise, the technician opened up the exhaust pipe, not the intake.

If I short the leads going into the switch, the error clears (obviously, but it does eliminate a wiring problem). Also, if I remove the tube from the intake and blow into it, the error clears (also not surprising).

When I was clearing out the nest, undoubtedly some of it fell down into the part of the pipe connecting directly to the burner box within the furnace cabinet. It's also possible there's a nest actually inside that last section of pipe, but I can't access it easily.

So the question is, how do I actually get at that part of the PVC intake pipe? Can I simply disconnect it by force? And if so, what sort of sealant would I need to put it back together?
 
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Old 10-23-11, 08:50 AM
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You can cut the pipe and use coupling with primer and glue ti put it back together or a rubber coupling with hose clamps. The key when cutting the pipe is to cut it straight.
 
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