what does pressure switch open mean on furnace

The furnace is a staple piece of home heating equipment that helps keep you and your family warm in the winter. But what does the term “pressure switch open” mean on your furnace? And why is it important to understand this concept? Understanding what pressure switch open means on your furnace can help you better maintain it and keep it running efficiently.

The pressure switch on a furnace works in conjunction with the blower motor. The switch is connected to an air chamber that senses a differential in pressure between the incoming and outgoing air. When the incoming air is higher than the outgoing air, the switch closes and allows the blower motor to turn on and circulate air through the ductwork. When the pressure differences equalize, the switch will open, and the blower motor will shut off. This keeps the motor from running unnecessarily and protects it from damage.

A pressure switch that remains open can indicate a few potential problems with your furnace. First, it could be caused by an obstruction or blockage in the system that is preventing proper airflow. This could be anything from a clogged filter to torn ductwork or a buildup of debris in the blower compartment. You should inspect the entire system for signs of an obstruction that could be causing the pressure switch to stay open.

In some cases, the pressure switch may be faulty and need to be replaced. If the switch on your furnace is not functioning correctly, it may not detect the pressure difference between the incoming and outgoing air accurately, resulting in the blower motor not turning on when it should. This can result in poor airflow and potentially cause overheating of the furnace components. You should have a qualified technician check your pressure switch and replace it if necessary.

Finally, the pressure switch may not close if the motor itself isn't working correctly. A weak or failing motor can prevent the pressure switch from closing, as the motor needs to generate enough air pressure to register a difference. If the motor is not able to create enough air pressure, the switch will stay open. If your motor appears to be failing, you should have it inspected and replaced if necessary.

Pressure switch open is a common issue on furnaces and understanding what it means and how to fix it can help you maintain your furnace and keep it running efficiently. Inspecting the entire system for obstructions, inspecting and replacing the pressure switch, and having the motor inspected and replaced can help resolve the issue and ensure your furnace is functioning properly.

How To Test A Furnace Pressure Switch