Ok, I got all my answers here during Summer on fixing my AC myself but now Winter is coming and my furnace is not working, AC works great but not the heat.

- system is Gas not Electric
- turned the TS to Auto and Heat but nothing only hear a click
- put it in ON and Heat and the blower turns on, I went to take a look at it and waited a few minutes but only the blower is working no flame
- checked all wiring and everything looks good

During summer when I was fixing my AC I replace the blower, trans, board and TS so they are all new about 6 months old.

Board:
Honeywell
Model - ST9141 A 1002
Part # - 406650

Led light gives 3 Flash: Pressure Switch-NC Circuit Open


TS:
White-Rodgers - 1F78H
Non-Programmable Thermostat


Please let me know if you have any suggestions or if you need some more information.

Thanks

Sounds like you have a stuck pressure switch or its wired wrong.

Thanks, I'll check that next

Forgot all about it after the weather got better but now the cold is coming and have not called anyone to look at it and will need it now to work.

So any other suggestions would help before I call someone.

Thank you

Just check as mentioned before.

Led light gives 3 Flash: Pressure Switch-NC Circuit Open

Check pressure switch for proper operation.

Check pressure switch hose to be sure it contains no water and has no holes or cracks.

Try removing the flue pipe from the inducer outlet, and BRIEFLY run the furnace. If it operates normally, the flue/chimney is blocked.