E09
Wolf Pressure Switch Stuck Closed

Furnace displays E09; inducer runs continuously without ignition.

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Safety Warning

This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.

If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.

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Possible Causes

Pressure switch contacts welded closed, Miswired pressure switch, Shorted pressure switch wiring, Control board sensing circuit fault

How to Fix / Troubleshooting

Safety: Disconnect power before testing continuity.

  • Visual check: Locate the pressure switch on the inducer assembly. Verify that only the factory-installed wires are connected and that no jumpers are present.
  • Continuity test: With power off and tubing disconnected, test the pressure switch terminals with a multimeter. The switch should be open (no continuity) when no pressure is applied. If it reads closed, the switch is stuck and must be replaced.
  • Wiring inspection: Check for pinched or shorted wires between the pressure switch and the Wolf control board.
  • Control board: If a new pressure switch still reads correctly but E09 persists, the pressure switch sensing circuit on the Wolf control board may be defective and require replacement.
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Repair Difficulty

Hard 4/5

Required Part

Wolf Pressure Switch
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