Originally Posted by spyvan
I am having trouble with a York diamond 90 gas heater. The unit blows cold air every few days. Once the power is cycled on the unit, it works and blows hot air. A HVAC company came out and stated that the fault lights is flashing 8 times and needs a new control board. The price is about $500 installed.
I found the part online York #33101972200 for $125.
How difficult is the control board replacement? It looks like a direct swap to me.
Depending what year your furnace is.
Your board probably isn't bad.
May have a dirty flame sensor.
A bad pressure switch.
Cracked hose running to a pressure switch.
A restriction in the venting.
Usually, when the board is bad, it won't recycle and give you heat.
Look on the furnace panel, at what code 8 indicates.