8531 Limit Switch Wiring ?
Am in the middle of a battle trying to swap out the limit switch from my spare 8531-lll I got from a guy, and the OEM 8531-ll in my Class C. I managed to get at the switch in the lll, but no luck y...
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'Limiting'....operation being controlled by High Temp Limit Switch shuts down DC to circuit board which closes gas valve but leaves Fan Running
When heat exchanger temp drops below High Temp Switch set point the DC is sent to Circuit Board and allows spark electrode/gas valve refire cycle.
Overfiring...LP pressure High or Orifice damaged
Discharge airflow obstructed/blocked----not enough ducts, too small of ducts, collasped duct(s), registers closed
Return Airflow obstructed/blocked.....items stored blocking return air, furnace casing return air blocked,
Fan Motor Speed....enough to make up sail switch but lacking enough airflow thru heat exchanger to transfer the heat generated
When heat exchanger temp drops below High Temp Switch set point the DC is sent to Circuit Board and allows spark electrode/gas valve refire cycle.
Overfiring...LP pressure High or Orifice damaged
Discharge airflow obstructed/blocked----not enough ducts, too small of ducts, collasped duct(s), registers closed
Return Airflow obstructed/blocked.....items stored blocking return air, furnace casing return air blocked,
Fan Motor Speed....enough to make up sail switch but lacking enough airflow thru heat exchanger to transfer the heat generated
