Shorted pressure switch, 1st stage.
American Standard S9V2 E3.1 is a shorted 1st stage pressure switch. The sequence proves both pressure switches open before the inducer starts, so a switch that is already closed or shorted fails that test. E3.2 is the 1st stage switch that stays open. E3.3 would be the shorted 2nd stage switch. Do not jumper either switch.
Likely causes
- 1st stage pressure switch circuit shorted
Safe checks for E3.1
- The heating sequence proves pressure switch 1 and pressure switch 2 open before the inducer starts. E3.1 is the 1st stage switch shorted, not the open-switch code E3.2
- Techniciancheck the 1st stage pressure switch circuit
Capacitors can hold a charge after the power is off. Safety terms.
When to call a pro
Call a licensed HVAC technician. Do not jumper a pressure switch.
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Furnace pressure switch: guide
In this code: 1st stage pressure switch circuit shorted
This one is for a technician to test or replace, so we only explain it and do not link to buy it.
Furnace inducer (draft) motor: guide
In this code: The heating sequence proves pressure switch 1 and pressure switch 2 open before the inducer starts. E3.1 is the 1st stage switch shorted, not the open-switch code E3.2
This one is for a technician to test or replace, so we only explain it and do not link to buy it.