SAIL SWITCH VOLTAGE CHECK
Hoping for help on troubleshooting a Furnace Sail Switch. Furnace was intermittently failing and now progressively worse. Blower would come on and after about 30 seconds would shut off - no audible at...
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I'd say there is a high resistance but not infinite resistance path around the sail switch. typical DMM input resistance is about 10Megohm. use the ohms function on the DMM an see what the open and closed resistance is. Open should be >>10Megohm, closed should be less a few ohms.
Also, the DMM is reading the voltage with no load applied. a closed resistance of even a few kohm with a 10Megohm input DMM will still read 12V, but be a high enough resistance to have the system think the sail switch is open,
Also, the DMM is reading the voltage with no load applied. a closed resistance of even a few kohm with a 10Megohm input DMM will still read 12V, but be a high enough resistance to have the system think the sail switch is open,
