I have a Unitary Products HVAC home unit and the A/C fan does not always come on when thermo kicks on, even though the condenser is running.
Sometimes the fan does not shut off when unit is shut off.
I suspect the control board is TU (bad). It is a 031-01267-001 per the PL.
Where can these be purchased? Is this the probable cause of this irregular operation? (i.e maybe a sticking relay on the circuit board/control board)?
Thanks

Check all thermostat wiring especially the G wire for the fan blower circuit.
It could be a relay on the board but good luck finding that relay.
Boards are expensive so I would make sure all wiring on the board/thermostat wires are good before replacing. I have no idea if you will need a different harness with the new style board. Best to ask them when ordering.

York, Coleman, Winchester Upgraded Ignition Control Circuit Board (Without Wiring Harness): Best Buy Heating and Air Conditioning (http://bestbuyheatingandairconditioning.com/Merchant2/merchant.mvc?Screen=PROD&Product_Code=CIB3101933&Category_Code=cb-coleman)

PartsGuy.com -- 031-01267-001 Control Module (http://www.partsguy.com/cgi-bin/PartsGuy/L38806.html)