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airheatman
airheatman, HVAC Technician
Category: HVAC
Satisfied Customers: 7724
Experience:  Furnace, A/C and heat pump specialist.
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Lennox package unit ignition control has slow blink

Customer Question

Lennox package unit ignition control has slow blink indicating normal operation w/o call for heat. However, thermostat is calling for heat (jumpered red to white to ensure). No combustion air fan operation until I open interlock circuit or remove 6-pin connector then both combustion and blower fans work until I reconnect.
Submitted: 1 year ago.
Category: HVAC
Expert:  airheatman replied 1 year ago.

Do you get any error code when inducer fails to start?

Customer: replied 1 year ago.
No, single on-board LED continues slow blink *approx. one per second)
Expert:  airheatman replied 1 year ago.

OK we still get slow blink on call for heat?

Expert:  airheatman replied 1 year ago.

And does this even with R and W jumped on board?

Customer: replied 1 year ago.
It's as if the unit doesn't see call for heat even though voltage measurements indicate otherwise.
Expert:  airheatman replied 1 year ago.

As you know we should get a fast flash on call for heat so I am going to say bad board at this point.

Customer: replied 1 year ago.
Second board -- same symptoms.
Expert:  airheatman replied 1 year ago.

Hmm. Are all the pins pushed into the connector good and making good contact at board?

Customer: replied 1 year ago.
I can measure in terminal points and all seem to have proper voltage.
Expert:  airheatman replied 1 year ago.

Ok on call for heat do you actually get voltage at the inducer?

Customer: replied 1 year ago.
Thermostat is calling for heat.
24 v to ignition control
No voltage on combustion fan terminal
Expert:  airheatman replied 1 year ago.

OK I would diagnose as bad board ,May have gotten a bad board out of box, but let me open to other experts who may have some other ideas. Please do not reply or rate answer as that will send question back to me. If no expert can assist, we can request a refund of your deposit if not satisfied, Again, just leaving a negative rating will not refund your money, just sends the question back to me to improve my answer.

Customer: replied 1 year ago.
Appreciate your help thus far. As I understand it others may respond. Will I be notified via text when/if additional answers are provided?
Expert:  airheatman replied 1 year ago.

That is correct. All other HVAC experts will see the question.If any have other idea, they will reply.

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