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Category: HVAC
Satisfied Customers: 14604
Experience:  15yrs in the HVAC industry with certificates and degrees.
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Lennox furnace won't go on-electronic ignition ignitor

Customer Question

Lennox furnace won't go on-electronic ignition ignitor replaced, brain replaced, relay replaced. Blower fan goes on when turned on - furnace won't goes. Thermostat clicks on, but nothing at furnace?
Submitted: 1 year ago.
Category: HVAC
Expert:  BillyHvac replied 1 year ago.


when you say blower it the exhaust fan that kicks on?

Customer: replied 1 year ago.
The blower fan on the furnace
Expert:  BillyHvac replied 1 year ago.

thank you.

have you checked the limit?

Do you have a voltmeter if needed?

was the filter plugged when this occurred?

Customer: replied 1 year ago.
Filter is changed every month filter is clear power going in but not sure if it is going anywhere after that that's why I replaced the relay
Expert:  BillyHvac replied 1 year ago.

Thank you.

Do you have a meter too see if we have 24v to and from thermostat?

Customer: replied 1 year ago.
No what's left if there isn't electricity flowing through what?? The relay and brain were both changed
Expert:  BillyHvac replied 1 year ago.

we have 2 different voltages...120v for the blowers...and 24v for the controls and thermostat.

This is done with the transformer. The main blower will run if transformer is bad.

we know the following:

blower motor works

new relay

new ignition control

this leaves the control circuit created by the transformer.


Customer: replied 1 year ago.
Does this mean change the transformer?? Which is where??
Expert:  BillyHvac replied 1 year ago.

see page 5 HERE

We could verify if you had a meter...but with the other items confirmed it leaves very few choices..which the transformer is #1

Customer: replied 1 year ago.
Thank You for your time
Expert:  BillyHvac replied 1 year ago.

you are very welcome,

If all set for now rate service and I will be available for follow up for 30 days.


Expert:  HVAC Guru replied 1 year ago.

If you have not a volt meter to test the transformer you do not need one, you can check a couple things at the control board to verify that instead of just replacing the transformer. If you need anything else just let me know.

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