how to test a furnace pressure switch with a multimeter

Believe your heating system stress button is acting up? Stress Change Panic? Grab Your Multimeter!

(how to test a furnace pressure switch with a multimeter)

That little heater pressure switch is a critical security guard. It sees to it the exhaust follower is really moving air out before the gas shutoff opens up. If it stops working, your heating system might refuse to begin or shut down suddenly. Don’t panic. Testing it yourself is frequently simple with a dependable multimeter.

First points first: Safety is non-negotiable. Turn off the power to your heater totally. Locate the main electrical switch near the system and flip it off. Additionally, shut off the gas supply valve. You do not desire sparks or gas surprises. Offer the heating system a few minutes to cool off.

Currently, locate the pressure switch. It’s typically a tiny, round, plastic or steel device near the draft inducer motor. One or two slim rubber or plastic tubes link it to the heater’s airing vent system. You may see cords causing an electrical adapter.

Gently disconnect those cords. You usually push a small tab and pull the port plug off the button terminals. This isolates the button for screening. Obtain your multimeter all set. Establish it to determine resistance, commonly shown by the Omega icon (Ω). This checks if power can flow with the switch.

Your pressure switch has terminals. You could see two or three. Focus on both terminals where the wires were connected. Touch one multimeter probe to every terminal.

Below’s the essential part: You need to simulate the pressure condition. Generally, the switch shuts (lets power via) when the inducer fan produces suction. You can * delicately * suck on the tube linked to the switch. Take care not to obtain wetness in it. Alternatively, if the heating system is trendy, you might briefly recover power just to allow the inducer fan run for a couple of seconds while you test. Only do this if you are incredibly certain and secure.

While applying suction (or with the follower running), check out your multimeter. A functioning switch ought to reveal extremely reduced resistance, near to zero Ohms. You may listen to a faint click inside the switch as it closes.

Release the suction (or turn power withdraw after screening). The button must open up. Your multimeter needs to now show extremely high resistance, often showed as “OL” (Open Loophole). This indicates no power can flow.

Got these two unique readings? Your pressure button is likely operating correctly. The problem might be somewhere else, like an obstructed air vent pipe, a split tube, or a defective inducer electric motor. Check those tubes for splits, kinks, or obstructions. Search for obstructions in the flue pipe.

No modification on the meter? The switch remains “open” even with suction? Or perhaps it remains “closed” also without suction? That normally implies the button itself is bad. It requires changing.

(how to test a furnace pressure switch with a multimeter)

Evaluating the pressure button with a multimeter provides you a solid answer. It cuts through the uncertainty. You confirm if this little security tool is doing its job or if it’s time for a brand-new one. Remember those simple steps: isolate, set the meter, apply suction, reviewed the results. It saves you a solution phone call. It gets your warmth back on faster. Simply constantly appreciate the gas and power. Job thoroughly. Your furnace will certainly thanks. Check those air vent tubes for pesky dust rabbits while you go to it.