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Jason Martin
Jason Martin, Handyman
Category: HVAC
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Experience:  One year systems installation and repair,
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My Trane XV80 is issuing a pressure switch error after the

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My Trane XV80 is issuing a 'pressure switch' error after the 2nd stage kicks in. Other Information: Burners are lit and blue, blower motor is running, plastic tubing behind the pressure switch looks clean/clear and is soft, pliable to the touch - doesn't appear old or worn. This is an older home, so the flue/vent is larger and metal. The flue has an animal cap. The outside temperature is -3 degrees and the furnace (only working in 1st stage, I suppose) is keeping the house at about 62 degrees. The thermostat is set at 70 degrees.
Hello and Welcome to JustAnswer HVAC

A quick question before we get into troubleshooting...

How does the filter look? Clean or dirty?
Customer: replied 7 years ago.
We changed the filter as our first step, and we change the filter monthly generally. It was not filthy, but we do have a long hair cat.
Ok, let's do a check of the pressure switch to see if it is sticking. Pull the hose off and blow into the hose to the pressure switch. It doesnt take a strong blow so don't blow too hard. You should hear a clicking noise. If not the switch is bad.
If it clicks, then put the hose back on and put the access panel back on. Turn your thermostat all the way up and it should fire back up.

Let me know what happened. I will wait here.
Customer: replied 7 years ago.

When I blow into the hose, it's like a soft crinkling sound - similar to the sound a vinyl beach ball makes when you blow it up after it's been flat. Is that the right sound? Also, I have turned the thermostat up to 80 degrees. I'll let you know what happens with that, but I wanted you to know the sound first.

That doesn't sound good. It should make a distinct clicking noise.

Just to double check a couple of other things, with the furnace off, check the inducer fan to see if it spins freely. If there is water or a blockage it will need to be removed.

Do this when you can and let me know, I will still be here.
Customer: replied 7 years ago.

You've lost me here. I don't know what an inducer fan is. Is that when the blower first starts to run before the second stage? I know this - you can't remove the filter while the furnace is on - even if you tried, because the air flow is so powerful.


There is also a small black fan in the back panel area near to the pressure switch and above the burners - it's unobstructed.


Does this help?

See pic below. The red arrow is pointing to the inducer fan. If this is ok, then your pressure switch needs to be replaced.

Customer: replied 7 years ago.

So, the black fan assembly above the burners is the inducer fan.


It's completely clear - and it's spins freely. I shut everything down again to make sure it's not damp - I see no sign of moisture - or even any dirt/dust.


The 'pressure switch error' is still flashing after second stage starts up.


So, is that something that a person can do themselves? Or, do I need to call a dealer?

You can do it only if you are confident in your own abilities. There isn't much to it, just turn the power off to the furnace at the breaker before you do anything.

Give me a second to see if I can find some pics or video of replacing it. I think I have run across a video of it before......
i have found this video on Youtube that shows testing the switch. So I dont know if this will help in replacing it. but atleast you get another idea on this issue.

i think you will find it is not difficult to do. just make sure you mark the wires so you will have reference to what wire went where.

Here is the video:

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Customer: replied 7 years ago.
You inspired me by telling me the switch had to be the problem. I was not afraid to mess with them after that. So, I completely disassembled all the hoses and took off the pressure switches - cleaned the tube feed on the high pressure switch with a pipe cleaner and a can of air. Then, I thought I would get a wire to trick the furnace just to warm up the house. While I was standing there thinking about how to do that. The second stage kicked in completely. The error code is gone. Thank you.
Awesome! Looks like you will have a very Merry and WARM Christmas!