This error code remains flashing through the next cycle until the moment that the furnace should activate then disengages and errors out again.
Trane gas furnace pressure switch error.
There s a motor engaging but after 5 speed ups the system disengages with the 3 flash error code for the inducer fan or pressure switch.
If the hose is cracked replace it.
4 a dirty or stopped up draft inducer.
The sensor closes when the furnace kicks in and allows heat to enter into the home.
The pressure switch is an indicator of pressure problems in the furnace.
Remove the main access panel on the front of the furnace.
Check the tubing from the inducer.
When a pressure switch error occurs the system will shut down and no warm air will enter the home.
And about 400 later the problem still existed.
The exhaust side of the pressure switch actually splits into two hoses.
One potential error is a furnace lockout which is not something that every furnace user knows about.
Inspect the pressure switch hose.
Vent pressure error three flashes on the trane furnace control board means that the vent pressure is too high or too low which then activates the pressure switch and causes a lockout.
This is for anyone experiencing pressure sensor limit switch issues with the xr series trane furnaces i went the end of one winter seasons and the beginning of the next trying to resolve this issue.
Some other things that cause furnace pressure switch problems are.
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.
The pressure switch fitting may have a restrictor inside do not remove.
Also the fittings that the tubing fit into should be clear.
Inspect the hose s connected to the pressure switch to make sure it is connected at both ends and is in good condition.
It should be clear.
Then three service calls a limit sensor a pressure switch a blower motor.
Other problems that could cause the pressure switch to not open are a dirty blower wheel on the inducer.
One goes to the gas valve and the other one goes to the bottom of the furnace where the burners are.
Let me clarify the bottom side of the pressure switch is the intake that has a small white flexible hose attached to it that runs down into air intake area.
