Can You Bypass A Pressure Switch On A Gas Furnace

With pump on should be closed allowing continuity.

Can you bypass a pressure switch on a gas furnace.

How to jump or bypass pressure switch on a furnace. Suck on the power hose and then check the switch again using the ohmmeter. Do not blow into a hose that is connected as this can damage the pressure switch. If is in the closed position the furnace stops the sequence and goes into lockout mode until the switch is open.

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. If a pressure switch is not jumpered correctly the furnace will not turn on at all. If your lennox does not activate normally during the ignition sequence try running a quick bypass of the pressure switch to determine if it is the problem. Remove the pressure switch hose s after carefully noting where it is connected if there is more than one hose remove and reinstall them one at a time.

This might free the switch from sticking. After all this the furnace should fire right back up. On newer furnaces on a call for heat the ifc checks the pressure switch. Next take off one of the power hoses and blow on it.

If you get a pressure switch code and the inducer will not come on remove one of the wires from the pressure switch. You can however test with a continuity tester testing with pump off and then pump on. Now use the ohmmeter to check whether the pressure switch is functioning properly. When you do this you should hear a clicking noise.

In no way do i recommend you attempt bypassing switch and should only be done by qualified technician. So go ahead and put the hose back on put the access panel back on the furnace turn up the thermostat to its highest setting. First turn the power of the furnace off. As long as the induced draft blower runs and there isnt a blockage in the flue then you should be fine.

This would only be d. It doesn t take much pressure so don t blow too hard. Sometime the switch itself the part buried within can fail. The pressure switch on a lennox g16 gas furnace monitors whether the air blower is in operation.

Honestly without seeing it in person i wouldn t be all gung ho about bypassing it. If you are working on a 90 condensing furnace move to the condensate drain.