Next take off one of the power hoses and blow on it.
Can you bypass a pressure switch on a gas furnace.
This would only be d.
It doesn t take much pressure so don t blow too hard.
Now use the ohmmeter to check whether the pressure switch is functioning properly.
Make sure the hose is not obstructed inside.
You can however test with a continuity tester testing with pump off and then pump on.
On newer furnaces on a call for heat the ifc checks the pressure switch.
Suck on the power hose and then check the switch again using the ohmmeter.
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.
The pressure switch on a lennox g16 gas furnace monitors whether the air blower is in operation.
First turn the power of the furnace off.
The switch activates with air force pushing a plunger in the mechanism which closes the circuit.
Take off the end so you can blow through it to the pressure switch.
Do not blow into a hose that is connected as this can damage the pressure switch.
If you get a pressure switch code and the inducer will not come on remove one of the wires from the pressure switch.
How to jump or bypass pressure switch on a furnace.
As long as the induced draft blower runs and there isnt a blockage in the flue then you should be fine.
If you are working on a 90 condensing furnace move to the condensate drain.
With pump on should be closed allowing continuity.
In no way do i recommend you attempt bypassing switch and should only be done by qualified technician.
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.
Honestly without seeing it in person i wouldn t be all gung ho about bypassing it.
When you do this you should hear a clicking noise.
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.
If a pressure switch is not jumpered correctly the furnace will not turn on at all.
Sometime the switch itself the part buried within can fail.