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path1's avatar
path1
Explorer
Apr 10, 2018

Magnet to test or re-set something in RV

I remember reading on here some time ago that a magnet is used to re-set or trouble shoot either suburban furnace or fridge (or something else in RV besides using magnet on trailer brakes). Hoping a magnet can re-set my furnace.

My problem is my Suburban furnace... is when I turn on t-stat mounted on the wall, I can here a little noise of a "clink" in furnace but the furnace doesn't start and can't here any spark or trying to fire off. This is not the wall t-stat noise. I have propane... stove works, fridge works that is right next to the furnace, so plenty of propane and batteries are fully charged and plugged into 110 volts . Model(take your pick) sf-20fq, sf-25fq, sf-30fq, sf35fq or sf-42fg I can't tell exact model yet because access to very limited.

Couple months ago I posted about the same furnace would start and would run for maybe 30 sec to a min and then quit. Finally got furnace to stay lit, At that time I thought spider webs were the problem. I blew out exhaust holes and ran a bottle of propane thru furnace thinking spiders would be cleaned out.

At that time responders to my post said most likely spiders or Hi Limit switch.

QuestionWhen and if a "hi limit switch" is bad can it make a "clink" noise?

7 Replies

  • path1 wrote:
    Model(take your pick) sf-20fq, sf-25fq, sf-30fq, sf35fq or sf-42fg I can't tell exact model yet because access to very limited.QuestionWhen and if a "hi limit switch" is bad can it make a "clink" noise?
    Here you go:Suburban Furnace Service Manual
  • for a magnet you can get a cattle magnet at most hardware stores were they have cattle in the area. good strong magnets
    Jay D.
  • When t-stat contacts close then 1st thing that must happen is furnace fan comes ON
    It runs for 30-90 seconds to purge combustion chamber and cause sail switch to close.....that then allows DC to flow to circuit board for spark and gas valve

    FYI.High Limit Switch is ALWAYS closed unless a high temp causes trip


    No Fan...NOTHING else can happen

    Fan power is controlled either by:
    Timed Delay Relay
    OR
    Blower Circuit On the circuit board

    What Brand/Model/Year is your Furnace?




    Good strong magnet is for resetting Norcold Recall Box 'reed switch' when tripped
  • A magnet can be used to reset the red light on the Norcold recall kit refrigerator safety over temperature trip.