After all this the furnace should fire right back up.
Furnace high pressure switch stuck open.
Replaced circuit board white rodgers 50a50 241 inducer motor comes on then get 3 fl read more.
If you have 24 volts the pressure switch is open and not proving the ventor motor.
This is not a repair.
Check for obstructions in the hose.
If the switch does not close after approx 1 minute the ifc goes into lockout mode.
On a few furnaces i have found the ventor motor seams to be running fine and power is good but fails on pressure switch.
The plunger may not be pulling in completely and may only bob around when the pressure builds up inside the furnace.
If there is no disconnect.
Tapping lightly on the pressure switch body may open the switch and the unit may start.
Which is why i made this video that go.
If the switch is open the inducer starts and the resulting pressure change closes the switch.
The pressure switch works with a small plunger that pushes in and out.
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.
Using a cloth and a wire brush remove any blockages and dirt from the secondary exchanger and the inducer.
Spray silicon lubricant on the plunger and work it back and forth to loosen the part.
When you do this you should hear a clicking noise.
Furnace pressure switch troubleshooting.
Inspect the pressure switch hose.
Turn off the power.
If your pressure switch is stuck it is most likely a problem in the running of the furnace.
Only oem pressure switches should be used.
Take off the end so you can blow through it to the pressure switch.
Or you test any voltage between 1 to 23 volts then you have bad contacts and the full power is not getting through causing the furnace to fail.
It doesn t take much pressure so don t blow too hard.
The pressure switch must be replaced.
Turn off the power to the furnace by switching off the disconnect switch located near the furnace.
Pressure switch stuck open replaced pressure switch still getting 3 flashes wich means pressure switch stuck open.
The source of pressure switch problems can sometimes be a pain to track down.
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