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Furnace worked fine last spring until we shut off end of…

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Furnace worked fine last...

Furnace worked fine last spring until we shut off end of May. Turned heat on this past Saturday and would not come on. Tech came yesterday and replaced thermostat and furnace ran immediately. Today furnace will not run. Purge blower comes on for 30 sec. and then shuts down and green light flashes on control board.

Contractor's Assistant: Did you double-check the thermostat's settings? And what about the filters?

Thermostat is set 5 degrees higher than inside temp., it is calling for heat, process begins as usual but stops after 30 sec. purge and green light flashes. Filter is new yesterday and furnace ran yesterday.

Contractor's Assistant: Do you plan on doing the work yourself?

Yes, I'm pretty handy - Manufacturing Engineer & I have a little knowledge about this furnace. If you think we can fix this now by doing something tonight then I'm all for it. If you think it's going to take special tools, parts, etc. then I'll call tech again tomorrow.

Contractor's Assistant: Anything else we should know to help you best?

Furnace quit last March - tech replaced "fan timer control board" and worked good until May when we had to start cycling power to furnace to get to run until it wouldn't run at all - tech then changed old mercury thermostat with new digital one and ran fine for few more weeks until heat no longer needed and then AC ran good all summer. Furnace would not start up for first time on Sunday - tech replaced thermostat again yesterday and immediately ran good until today. Propane tank full, furnace does initial 30 sec. purge but then shuts off immediately w/ green light flashing and does not continue the sequence to initiate "trial for ignition", I have tools & multi-meter.

Submitted: 11 months ago.Category: HVAC
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Answered in 15 minutes by:
10/18/2017
HVAC Technician: HVAC Guru, HVAC TECH replied 11 months ago
HVAC Guru
HVAC Guru, HVAC TECH
Category: HVAC
Satisfied Customers: 18,897
Experience: 20yrs in the HVAC industry with certificates and degrees.
Verified

Hello, one minute while I get some information together.

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HVAC Technician: HVAC Guru, HVAC TECH replied 11 months ago

What code is flashing on the board?

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