The Wall
Forum / THE MAIN WALL / Honeywell pressure switch
  • Post a Reply to this Thread

    Honeywell pressure switch (6 Posts)

  • ChrisJ ChrisJ @ 10:18 AM
    Contact this user

    Honeywell pressure switch

    Has anyone noticed a lot of these Honeywell pressure switches failing on Luxaire/York furnaces?   Its the one that measures pressure difference between the exaust and intake on direct vent systems.

    The switch I'm looking at is a model 9371-DO-HS-0010 and it has failed already in less than a year after replacing the first time.  Now, giving it a bump will get it working again for a while until it sticks again (sounds real safe, right?).
    Weil-McLain EG-45 connected to 392sqft of radiation via two 2" risers into a 3" drop header and 2" equalizer. Using Rectorseal Steamaster water treatment to greatly reduce corrosion in the boiler.

    Steam system pictures updated 6/5/14.
    https://picasaweb.google.com/thetube0a3/Boiler?authkey=Gv1sRgCImUxIqv9436MQ#
  • Timco Timco @ 8:25 PM
    Contact this user

    Is it...

    A positive or negative pressure switch? (monitors inducer or HX)

    I've found on reoccurring issues the number of elbows or length or vent was right at max.
    Working on steam and hot-water systems isn't rocket science....it's actually much harder.
  • ChrisJ ChrisJ @ 10:59 PM
    Contact this user

    negative

    It says -1.00WC on it so I'm assuming thats a negative pressure switch.

    I know the exhaust and intake lines are almost identical, one has an extra 45 to offset it some. Also the lines are 1 elbow short of the recommended maximum except the intake has that extra 45 which moves it even closer to the max I guess.

    Would modifying the lines and removing any elbows possible give the switch less of a chance of failing?
    Weil-McLain EG-45 connected to 392sqft of radiation via two 2" risers into a 3" drop header and 2" equalizer. Using Rectorseal Steamaster water treatment to greatly reduce corrosion in the boiler.

    Steam system pictures updated 6/5/14.
    https://picasaweb.google.com/thetube0a3/Boiler?authkey=Gv1sRgCImUxIqv9436MQ#
    This post was edited by an admin on December 9, 2012 11:00 PM.
  • Timco Timco @ 12:14 AM
    Contact this user

    Yes

    I would say not being 1 45* elow from max would surely help. Fieldpiece makes a sweet new pressure switch testing instrument but I don't have one yet because a failed pressure switch is uncommon. It's more likely your altitude or fittings/pipe size being near max. You can increase pipe size if fewer fittings is not possible. Use your analyzer to test negative pressure at the inducer.
    Working on steam and hot-water systems isn't rocket science....it's actually much harder.
  • ChrisJ ChrisJ @ 9:55 AM
    Contact this user

    altitude

    Altitude is around 2000 feet.

    After looking at it we decided we can eliminate 4 90 deg ells and replace them with 3 45s.


    Thanks for your help, I appreciate it.
    Weil-McLain EG-45 connected to 392sqft of radiation via two 2" risers into a 3" drop header and 2" equalizer. Using Rectorseal Steamaster water treatment to greatly reduce corrosion in the boiler.

    Steam system pictures updated 6/5/14.
    https://picasaweb.google.com/thetube0a3/Boiler?authkey=Gv1sRgCImUxIqv9436MQ#
    This post was edited by an admin on December 10, 2012 9:56 AM.
  • ChrisJ ChrisJ @ 12:32 PM
    Contact this user

    Update

    So my dad said another pressure switch failed a few days ago. He installed another new one and all is well again.

    Seems they go around a year before giving a "stuck open' error. Doing a quick search seemed to bring up a lot of pressure switch failures on York / Luxaire units but nothing specific other than a service bulletin saying they changed the switch to deal with contaminants from the silicone hoses.

    Still haven't changed the venting arrangement although I think my dad is seriously considering it now. Either that or calling his heating guy out to see if something else isn't right.
    Weil-McLain EG-45 connected to 392sqft of radiation via two 2" risers into a 3" drop header and 2" equalizer. Using Rectorseal Steamaster water treatment to greatly reduce corrosion in the boiler.

    Steam system pictures updated 6/5/14.
    https://picasaweb.google.com/thetube0a3/Boiler?authkey=Gv1sRgCImUxIqv9436MQ#
    This post was edited by an admin on January 13, 2014 12:32 PM.
  •  
Post a Reply to this Thread