How to Test Pressure Switch on Furnace
Testing the pressure switch on a furnace is an essential task to ensure the safe and efficient operation of your heating system. The pressure switch plays a crucial role in monitoring the pressure inside the furnace, preventing potential hazards such as explosions or leaks. In this article, we will guide you through the steps to test the pressure switch on your furnace, ensuring that it is functioning correctly.
Understanding the Pressure Switch
Before diving into the testing process, it’s important to understand the purpose and function of the pressure switch. The pressure switch is a safety device that monitors the pressure inside the furnace. It is typically installed on the furnace’s combustion chamber or the exhaust vent. When the pressure inside the furnace exceeds a certain threshold, the pressure switch will open the gas valve, shutting off the gas supply and preventing any potential dangers.
Preparation for Testing
Before testing the pressure switch, make sure to gather the necessary tools and materials. You will need a multimeter, a screwdriver, and a safety mask. It is also crucial to turn off the power to the furnace to avoid any accidents during the testing process.
Step-by-Step Guide to Testing the Pressure Switch
1. Locate the Pressure Switch: The pressure switch is usually located on the furnace’s combustion chamber or the exhaust vent. Once you find it, inspect the switch for any visible damage or signs of wear.
2. Identify the Connections: Use a screwdriver to remove the cover of the pressure switch. You will see two terminals or wires connected to the switch. These are the connections that will be tested with the multimeter.
3. Set Up the Multimeter: Set your multimeter to the ohms (Ω) mode. This mode will allow you to measure the resistance between the two terminals.
4. Check the Resistance: Touch the multimeter probes to the two terminals. If the pressure switch is functioning correctly, you should read a specific resistance value, which can vary depending on the manufacturer’s specifications. If the resistance is too low or too high, the pressure switch may be faulty.
5. Perform the Pressure Test: To further test the pressure switch, you can perform a pressure test by using a pressure gauge. Connect the gauge to the pressure switch and increase the pressure gradually. The switch should open the gas valve when the pressure reaches the specified limit. If it does not, the pressure switch may be malfunctioning.
6. Inspect the Gas Valve: After testing the pressure switch, inspect the gas valve for any signs of damage or wear. A faulty gas valve can also cause the pressure switch to fail.
7. Reset and Re-test: If the pressure switch is found to be faulty, replace it with a new one. Once the new switch is installed, repeat the testing process to ensure it is functioning correctly.
Conclusion
Testing the pressure switch on your furnace is a critical step in maintaining the safety and efficiency of your heating system. By following these steps, you can ensure that your pressure switch is in good working condition and prevent any potential hazards. If you are unsure about the testing process or if the switch is found to be faulty, it is always best to consult a professional HVAC technician for assistance.
