Trane XE 90 pressure switch

Discussion in 'HVAC' started by eddie, Feb 24, 2006.

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  1. Jan 26, 2012 #41

    pookie16

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    Wind gusts on the roof causing back pressure in the flue. This would not depend on the physical location of the actual furnace. That is what I meant. It makes sense to me, and I say it is a bad design in that if the wind caused back pressure, and then the situation is resolved, it should not require manually reseting the furnace. If I was king, I would change it so that if the furnace is running for several hours in 3 blinks mode, it should reset itself.
     
  2. Jan 27, 2012 #42

    Furnaceguy59

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    It shouldn't require resetting the furnace and Trane knows this. And, I think the dealers know it. And, there's nothing they can do about it unless you replace logic boards with updated firmware. I have no way of knowing this but I'm sure either the firmware has been updated and/or the pressure switch is different on newer models. When I get some time, I'm going to prove my, and my tech's theory. I'm going to take my leaf blower outside and blow varying degrees of wind into the exhaust and intake pvc runs to see if I can duplicate a strong gust of wind resulting in a change in pressure on the switch, shutting the furnace down and getting the 3 blinking lights.
     
  3. Jan 27, 2012 #43

    paul52446m

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    Any 90+ furnace can be effected by outside air blowing into the stack That is why i don't like venting them through the side wall. I would rather go through the roof. If you have wind problems and you are through the side wall. instead of going straight out, you might want to but a tee so the wind can't blow in. I live in a cold area and when we first started with the 90+ furnaces we were told by the factory how to run the stacks and we had to start changing the way we run stacks right away. I usually run the intake pipe it a vented attic with a 1 foot long screen on it. This way the wind will not bother it as much. If i have to side wall vent, i try to go out where i will not get the prevailing winds. Some times just reducing the stack on the out side will blow the fumes out harder so it will maintain better pressure in the stack and the wind will not bother it as much. Paul
     
  4. Feb 16, 2012 #44

    lostpilot28

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    Just wanted to post a quick update...I finally got my XE90 fixed. The heat exchanger was replaced, because the old one had a huge crack in the plastic interface part where the exhaust gas exits. :eek: Surprised I'm still alive to tell you about this! :D

    Anyway, that huge crack was allowing the pressure to normalize between the front and the back burners...when it should've been over 1.5" H2O, it was only around .9".
     
  5. Oct 29, 2012 #45

    MarkBean

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    THANK YOU! You helped me restore heat to my house just as hurricane Sandy is hurtling towards us. I scanned the internet looking for ways to solve this problem. After over an hour of educating myself on how to troubleshoot/repair I went up into my attic with all a number of tools, WD40 and my voltmeter. The one "tool" that solved the problem was a paper clip. I didn't see any blockages but after removing the tube and then sticking a paper clip in the tiny hole of the blue valve of the pressure switch, I was back in business.

    Now I'm just a bit concerned and want to make sure that I didn't possibly hurt the pressure switch and put it into a permanent on mode by pushing the paper clip in until it stopped. I'd sleep a bit easier if someone could confirm that one can't hurt the switch in this manner.

    On another note, I did see some bug carcases behind the glass porthole before the burners. Should I be concerned about them?
     
  6. Oct 30, 2012 #46

    Bigdog1

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    I too checked the bottom trap for clogs and dirt. Nothing. Exhaust Fan motor works. No problem with my flue pipes.

    Did the old paper clip trick and the furnace is running.

    I had to do it a few times because I don't think I was deep enough the first couple times. But I also wanted to be gentle...

    It's very windy and I have had this problem before during WIND events...

    Piss poor design if you ask me...Nothing keeps the repairman coming back like a Trane.

    On a side note my heat exchanger has already been replaced because of a huge crack...and the BLOWER motor too...

    The last time I had a 3 flash problem the water trap at the bottom was clogged...That was my first stop this time...

    Thanks guys....:trophy:
     
  7. Oct 30, 2012 #47

    nealtw

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    MarkBean and Bigdog1; Sorry I can't offer any insight but welcome and thanx for sharing.
     
  8. Oct 30, 2012 #48

    Bigdog1

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    The problem came back. I did the paper clip again and the furnace fired up but it has since shut down again.
     
  9. Oct 30, 2012 #49

    pookie16

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    I see I never posted an update. I was working out of town and my wife was shutting the furnace off and restarting it to keep the house warm. I got a repair man in. His theory was that if the cycle time was too short, the vacuum in the flue was not dropping enough to let the switch open. He put a smaller diameter and longer hose to the switch and increased the temperature differential to restart the furnace. It seemed to work, so he left with some of my cash, but with the guarantee to come back if the problem was not fixed. A day later, the problem came back. I was out of town and my wife went back to restarting the furnace manually. Before I got back to town, the problem just went away. It is now a year later or so and the furnace seems to be working.
    I will reiterate the person's comment that said this is a poor design. I also thought Trane was a good brand when I bought this new furnace. The old one (FlameMaster) supposedly had a leaky heat exchanger, but it worked for 17 years that way with one belt replacement. This new one has broken down on two different problems in 3 years.
     
  10. Oct 31, 2012 #50

    Bigdog1

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    Well this is interesting.

    It stopped working again and went back to three flashes. I did the paperclip thing again a few more times. It would light and shut down. I took the hose off to the presure switch and the furnace fired up and ran like normal. With the hose off now it has been running normal for 24 hours...WITHOUT THE HOSE...:confused:


    Furnace repair guy is coming this morning...I can't wait to hear what he says about how it's running normally... and flashing no code.
     
  11. Oct 31, 2012 #51

    pookie16

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    Bigdog1: that is sort of scary since the purpose of all of this is to assure the house is not filling up with CO. All the problems we are having to keep us safe and yours works now with the safety devices bypassed. I will have to say again, poor design.
     
  12. Oct 31, 2012 #52

    Wuzzat?

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    Dangerous, from CO & possibly from NG.
     
  13. Nov 1, 2012 #53

    lostpilot28

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    Sounds like what I went through. Basically, with the hose connected, the heater would stop working...pressure in the upper part of the heater was too high, and the pressure switch would (rightfully so) shut it down. 3 flashes of the LED.

    Swapped the pressure switch, cleaned EVERYTHING inside and out. Still only worked (most of the time) with the pressure hose disconnected.

    The Fix: got a new heat exchanger (under warranty I think - 10 year old XE-90). The repair guy pulled the old one out and you could see a HUGE crack on the plastic part of the heat exchanger where it mates up to the blower. The crack was probably 1/4" wide and about 10 inches long.
     
  14. Nov 1, 2012 #54

    Bigdog1

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    Well the repairman was stumped for a while....

    We changed the pressure switch and it works fine now.

    You could hear a tiny rattle in the old pressure switch...maybe something got sucked into it....and one of the hoses had a small piece of something in it.

    My heat exchanger had a big crack in it and it ran for a long time like that.

    I had a carbon monoxide alarm plugged in right beside the furnace. It kept going off and I unplugged it...:eek: moral of the story...always trust the alarm....but in my defense....it kept saying gas and there was no gas leak...maybe it classified carbon monoxide as a gas...leak
     
  15. Nov 1, 2012 #55

    Wuzzat?

    Wuzzat?

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    IIRC correctly there is a min. spacing req'mt between fuel burning appliances and CO detectors.
     
  16. Nov 2, 2012 #56

    Bigdog1

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    I built a room that houses my gas furnace, gas water heater, washer & gas dryer.

    I had the CO detector plugged in behind the dryer which is right beside the furnace.

    Actually I haven't had one in use now for 10 years. :eek:

    I think it's time to buy a new one and install it.

    One more thing about the furnace pressure switch issues. This same 3 flashes problem happened last year and it always seems to be an issue when we have a heavy WIND event. Wind is not a friend to my furnace operation.

    My heat exchange crack was found in the middle of winter. I had to wait 1 1/2 weeks for the part to come from Texas. Nice....keep all the spare furnace parts in Texas during the winter....which Texas doesn't have much of. Probably 90% of the furnaces sold in the country are in the Northeast. Keep the part down south....

    And now about my "furnace room."


    Insurance companies claim about 90% of house fires start from gas appliances.....so I installed a sprinkler head in the middle of this room which will cover all of these appliances with water coverage.

    I got an old liquid type (has a yellow liquid in it that will start to boil and the glass will break opening the sprinkler) sprinkler head from work.

    Just ran a tap off the cold water line running into my room.

    I did mention my "sprinkler" system to the insurance company. It should knock off a few dollars in your premium payment and it gives you a greater chance of surviving a fire and saving the house.

    This is also where I have to install my new CO detector.
     
  17. Nov 2, 2012 #57

    Wuzzat?

    Wuzzat?

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    Do they mean:
    Given that you have a fire there's a 90% chance it started from a gas appliance?

    or

    Given that you have a gas appliance there's a 90% chance that it will start a fire?

    These two conditional probabilities are seldom the same.

    And, see what the gas appliance makers say about the cause of house fires. The truth may be in the middle somewhere, or nowhere near what either entity says.
     
    Last edited: Nov 2, 2012
  18. Nov 3, 2012 #58

    Bigdog1

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    Just having a gas line going into your house is probably enough of a percentage without anything hooked to it.
     
  19. Nov 12, 2012 #59

    MarkBean

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    It turns out that the paper clip trick did not solve the problem. The furnace ran for a bit and then had the same code. I tried it again with the same results. I banged on the intake a bit and some more bug carcases dropped down. Not a lot but enough to notice the difference. We were then without power for a week due to Sandy. The furnace has been working fine ever since we got power restored. My guess is that I have/had a partial blockage in the intake. This weekend's project is to take put my shop vac on reverse and try to blow out anything that may be in the intake. After that I'll put in on forward and clean out the carcases.

    Thank you for the information.
     
  20. Jan 18, 2013 #60

    Danza

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    I'm in the same boat with my trane xe90. I've had the front side hose disconnected from the vacuum pressure switch (there's 2 hoses, one on each side) for over a year and its been working just fine. But before that and if I reconnect it now it will quite and give me the 3 led flashes.
    My main concer is having that hose unplugged might cause dangerous gas to go into the home? Second and less of a concern is its working efficient.
    Appreciate any help!
     

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