York RTU fault code

[icyhotnyc]

model # d2ga024n04806b
serial # nhbm056819
Customer stated someone else has looked at the unit and had it running for a day, but now it has stopped again.
Fault code is flashing 4 times.
Previous mechanic jumped roll out switch and high limit switch.
Circuit board would not reset after power shut down, still reads 4 flashes.
If no safety circuits are open, it must be the circuit board.
Only the two safetys are on the schematic.
There is no fault code key printed on the unit.
What is 4 flashes?

[trane]

4 flashes means that the switch in the ventor motor is not closing. There is a centrifugal switch on the bottom shaft of the ventor motor that has to make when the motor runs. There will be two red wires going to the switch in the bottom housing. You might check for wasp nests in the housing that keeps the switch from working or the blower or switch are bad.

[icyhotnyc]

ah, the inducer fan motor never came on, and the flashes came on instantly. I will check for voltage now at the motor. If no voltage then I have to replace the board. I looked all over for fault codes, they never printed them on the unit. Thank you for your help.

[trane]

This unit was a big mistake by York with alot of problems including the board and ventor motor. Check the heat exchanger for splits in the tube and there is a good chance you will get to sell them a new one.

[icyhotnyc]

here's an update:
went back right before the blizzard hit, and sure enough it was the inducer fan motor.
it's a small apartment building(4 small 1 bedroom/studio)
The funny thing is after I started up the unit (which was fine), the lady asked why isn't there heat in two of the four apartments? I go back to the roof, previous owner had installed a separate RTU for each apartment. TWO more fan motors to be replaced!!!
Blizzard hit hard so will have to wait till Monday, supply houses closed early today.