Furnace pressure safety switch: what it does and when to replace it

A furnace pressure safety switch is a device used in heating systems to protect against overpressure or loss of pressure. It shuts off the furnace if the pressure in the combustion chamber moves outside a safe range, which can signal a dangerous problem.

Because this switch is a key safety component, it is worth understanding what it does and when it may need attention.

What the pressure safety switch does

• Protects against pressure problems: it guards the system against both overpressure and loss of pressure in the combustion chamber.
• Shuts the furnace down: it cuts off the furnace when pressure exceeds a safe limit, which could point to a blocked flue or a malfunctioning fan.
• Frequent tripping is a warning: if the switch trips often, it may indicate an underlying furnace problem that needs to be addressed.
• Works with the inducer draft: the switch confirms the furnace is drawing proper draft before the burners are allowed to ignite.
• A switch that never trips can be faulty: if it does not trip when it should, the switch itself may be defective and need replacement.

Keeping the pressure safety switch in good working order is essential to the safe operation of any furnace. If you are unsure about how your switch is functioning or suspect it needs to be replaced, it is best to consult a professional HVAC technician. Nur HVAC can diagnose the issue and, if necessary, install a new pressure safety switch to restore safe operation.