High Efficiency Furnace Pressure Switch Problems

Some other things that cause furnace pressure switch problems are.

High efficiency furnace pressure switch problems. If your pressure switch is stuck it is most likely a problem in the running of the furnace. Holes tears or other damage to the diaphragm. Water in the vent due to a sag in the piping could cause a pressure switch not to close. The most common problem on high efficient furnaces would be frost or water in the vent.

Using a cloth and a wire brush remove any blockages and dirt from the secondary exchanger and the inducer. Problems a furnace pressure switch can develop. If you have a high efficiency furnace then you probably have a condensate drain and if the condensate drain becomes clogged up it will cause pressure switch problems. First off the furnace being high efficient will produce water due to low vent temperatures and condensation in the vent pipe.

Of course the pressure switch may also shut down if the motor is old and running too slow to satisfy the switch or the hose from the fan to the switch is pinched or broken or the switch itself is bad. Old age which can cause inaccurate readings and faulty furnace cycling. A crack in the heat exchanger could also be at fault. 4 a dirty or stopped up draft inducer.

If the condensate drain is blocked by debris or frozen condensate or it simply drains improperly the pressure switch may open preventing ignition. Coated or stiffened pressure switch diaphragm. The plunger may not be pulling in completely and may only bob around when the pressure builds up inside the furnace. A bad switch or a tripped switch is a common cause of furnace malfunctions.

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. Ice on the venting or a plugged screen on the vent termination only on 90 efficient furnaces could also be the problem. Pressure switches may act up for several reasons including.