Vokera Air Pressure Switch Open When Should Be Closed

Code 40, furnace fan runs but burner does not light, may indicate air pressure issue

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

Blocked flue or air intake, Faulty air pressure switch, Split or blocked pressure tubing, Fan not achieving speed

Safety: Isolate power before opening the casing.

Check flue terminal: Ensure the terminal is clear outside.
Inspect pressure tubes: Remove and check the silicone tubes from the fan to the air pressure switch. Clear any water or debris and refit securely.
Check switch operation (qualified persons): Gently blow into the switch port and listen for a click. No click may indicate a failed switch.
Do not bypass: Never bridge or bypass the air pressure switch; this is a critical safety device.

Hard 4/5

Air Pressure Switch

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