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  1. #1
    Join Date
    Jan 2012
    Location
    Alsip il
    Posts
    89

    stuck pressure switch on york furnace

    was on a call today and ran across a stuck open pressure switch fault on a york furnace. 90% 80,000 btu upflow modulating natural gas furnace.

    model# YP9C080B12MP11A
    serial# WOE8871705

    was able to unstick pressure switch and is working fine now. i found a couple of droplets of condensation at pressure switch port and in tubing. this is the pressure switch off of inducer motor and not the one tat goes to the secondary heat exchanger cover. even though everything is working now i have a feeling that the same problem will result.

    thanks for your help.

  2. #2
    Join Date
    Feb 2012
    Location
    san pedro ca.
    Posts
    362
    replace it.

  3. #3
    Join Date
    Nov 2010
    Location
    N. Idaho
    Posts
    586
    So are you asking a question or just telling us how your call went?!
    "I've got my Gas Mechanics license"
    "Yea, well my 16yr old daughter has her drivers license, doesn't mean she knows how to drive"

  4. #4
    Join Date
    Jan 2012
    Location
    Alsip il
    Posts
    89
    sorry i guess what im asking is is what would make the condensation get all the way to the pressure switch? the inducer is pulling a negetive pressure. are the pressure switches used on york poorly constructed or is there a issue i can be missing. i have run into a similar problem on other york 90% furnaces that are less than 5 years old. not modulators though.

  5. #5
    Join Date
    Nov 2010
    Location
    N. Idaho
    Posts
    586
    Maybe I'm not sure where your seeing the condensate but there is always some moisture in the inducer housing. I suppose some could have found its way down that tube. Maybe you got enough in there it couldn't close, i dunno. I would just replace it though.
    "I've got my Gas Mechanics license"
    "Yea, well my 16yr old daughter has her drivers license, doesn't mean she knows how to drive"

  6. #6
    Join Date
    Jun 2011
    Location
    Seattle WA
    Posts
    1,245
    You are working on one of the first ones that came out (MP11A). These had alot of condensate/pressure switch problems. Are you sure it was actually stuck or did you just reset it? These older ones didn't come with the pigtail loop in the pressure hose that comes off of the inducer. They all come with this little loop in them now that diverts the condensation back to the inducer, otherwise it messes with the transducer and any little bit of condensation buildup will cause it to throw a pressure switch code. Check all the drains to make sure they have perfect fall, also make sure the pressure hose that connects to the collector box is on the top port. I would also tell your distributor to give you the little pigtail hose that goes from the inducer to the transducer

    *EDIT: They have also changed the specs on the pressure switches in newer models...
    America; first we fight for our freedom,
    then we make laws to take it away.

    -Alfred E Newman

  7. #7
    Join Date
    Jan 2012
    Location
    Alsip il
    Posts
    89
    liberty, thanks for the help. the pig tail makes sense and ive seen that on other models. switch did not reset on its own untill i got moisture out of hose.

  8. #8
    Join Date
    Jun 2011
    Location
    Seattle WA
    Posts
    1,245
    Quote Originally Posted by Furnaceguy85 View Post
    liberty, thanks for the help. the pig tail makes sense and ive seen that on other models. switch did not reset on its own untill i got moisture out of hose.
    no prob, the pressure hose from the collector box being on bottom instead of top can apparently cause the line to accumulate condensation, make sure to check that next time you go out. Funny thing is that the manual says to put it on the bottom port, the York service guy had to have classes for its dealers telling you what to disregard in the manual LOL
    America; first we fight for our freedom,
    then we make laws to take it away.

    -Alfred E Newman

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