A055_F: Inducer High Pressure Switch Won't Open
Status
This is a critical fault. The furnace will not operate in gas heat modes but all other modes (e.g. cooling) should function. This fault only occurs on 90+ furnaces.
Description
The high pressure control (or switch) should not be closed when the inducer is not running. If it is, this is a sign of a serious condition. The switch may be welded closed or purposely bypassed in the field. Before any heat cycle can begin, the pressure switch is tested to make sure that it is opened. The switch is ignored except in gas heating modes.
Expected Operation
Gas heating will not be allowed. Alarm "A055_F Inducer Hi Pressure Switch Won't Open" will be logged if a heat demand is present.
Cause
1. Faulty Switch
2. Pressure switch physically bypassed in the field.
3. Loose or faulty wiring.
4. Abnormally high negative pressure present on vent system without inducer running.
Solution
1. Replace high pressure control (switch).
2. Remove bypass and restore correct operation. Determine reason for bypass (e.g. vent length too long) and correct issue.Notify homeowner and proper authorities of illegal tampering if necessary.
3. Check wiring and connections. Replace and/or repair as necessary.
4. Check for proper venting and terminations as defined in the furnace installation instructions.
