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Pressure switches

Bob C._2
Bob C._2 Member Posts: 31
in THE MAIN WALL
What is best procedure to test pressure switches hi and lo fire

also best way to check to see if secondary heat exchanger is clean and ok?

Comments

  • furnacefigher15
    furnacefigher15 Member Posts: 514
    Test procedure

    When on furnace:

    Run the inducer, and check the pressure with a manometer, or magnehelic gauge. If the vacuum is more then rating on the switch, it should electrically change position.



    If outside of unit, you can create a vacuum with a hand vacuum pump. like the ones they use in the automotive world. Check the amount of vacuum in the same method as outlined above.



    Note if the pressure switch has 2 ports, like on a 90% furnace, then the only accurate way to test is with a 2 port manometer connected to the same points as the pressure switch.



    Secondary HX



    Visual inspection. Remove collector box to inspect inside.
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