CTC Stuck Pressure Switch or Faulty Ignition Sequence

Furnace inducer runs continuously but burners do not ignite.

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.

Possible Causes

Pressure switch stuck closed, Faulty control board logic, Shorted pressure switch wiring, Blocked condensate causing false draft signal

Safety first: Turn off power and gas before testing switches.

Steps:

With power OFF, disconnect one wire from the CTC pressure switch and test for continuity across the switch with no call for heat. It should be open; if closed, the switch is stuck and should be replaced.
Inspect pressure switch tubing and inducer ports for water or debris and clear as needed.
Check condensate drain for blockages that may affect pressure readings.
If the switch operates correctly but the inducer never proceeds to ignition, the control board may be at fault.

Hard 4/5

CTC Draft Pressure Switch

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