Gas Furnace Pressure Switch Failure To Close

Furnace pressure switch not closing.

Gas furnace pressure switch failure to close.

Water in the vent due to a sag in the piping could cause a pressure switch not to close. Remember the pressure switch doesn t close until the inducer motor comes on and provides the necessary suction for the pressure switch to close. Some other things that cause furnace pressure switch problems are. Or if it s perhaps condensation related and replacing the switch won t solve the problem.

When we re troubleshooting a furnace pressure switch we can do a few things. Ensure the draft is above the required pressure. Continue reading below our video of the day. Check the inducer wheel to see if it is damaged.

If the multimeter does not show any sign of change in continuity and the switch fails to close this is a sign that your pressure switch is faulty. Other problems that could cause the pressure switch to not open are a dirty blower wheel on the inducer. The draft inducer fan motor will begin to run. I can find the pressure switch but not the venter or vent.

It also has this nifty little diagram on the back that tells me what the problem is. The inducer motor may not be coming up to speed due to failing bearings. By this point on an 80 efficiency furnace if you haven t found the culprit you will have to put on your best thinking cap because the issue could be any number of things including a bad board loose or bad wire connections or a bad pressure switch. A gas furnace pressure switch closes to allow current to pass through and start the ignition of the furnace.

If the pressure switch is stuck it does not send enough power to the inducer and therefore the ignition sequence does not begin. A blockage in the vent will also cause a pressure switch to not close. 3 blinks pressure switch failure to close says to check venter pressure switch vent blockage. 1 a restricted vent pipe 2 too long of vent piping and too many turns which exceeds manufacturer s recommendations 3 a stopped up condensate drain line if you have a high efficiency condensing furnace.

So what i m trying to figure out is if it should just replace the pressure switch i hear this model is failure prone hk06zb104. The pressure switch has a pressure at which it closes which is typically negative. Turn the furnace on. If that is the tube running from the pressure switch it s clear.