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Ask Mark Henley Your Own Question
Mark Henley
Mark Henley, Journeyman Technician
Category: HVAC
Satisfied Customers: 3217
Experience:  UA Journeyman Pipefitter , HVAC, Refrigeration, DDC controls. 26 years.Commercial & residential
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My heil gas furnace has no fire or heat

Customer Question

My heil gas furnace has no fire or heat
Submitted: 7 years ago.
Category: HVAC
Expert:  Mark Henley replied 7 years ago.

Hi,

 

Can you tell us what it does if you turn the thermostat off and then back on, see if it makes nay noises and if the vent fan comes on. That will help us help you.

 

Thanks

 

Mark

Customer: replied 7 years ago.
the vent fan runs when thermostat is turned on and makes a slight noise might be blower
Expert:  Mark Henley replied 7 years ago.

Hi,

 

OK is there a small window on the door of the furnace where you can see an LED lit ? If so it is probably flashing a code on there, could you check that ?

 

Thanks

 

Mark

Customer: replied 7 years ago.
clear plastic cover on a box where gas line goes into burner. not seeing anything. Did not see any where else to view
Expert:  Mark Henley replied 7 years ago.

Hi,

 

OK if that vent motor runs but you do not get any ignition it is probably a pressure switch problem , its a pie-tin shaped device with 1/4" hose attached to it and a couple wires, do you see that ?

 

Thanks

 

Mark

Customer: replied 7 years ago.

I see it

Expert:  Mark Henley replied 7 years ago.

Hi,

 

OK if you can take the hose off and blow it out and also clean out the barbed fittings that it attaches to and try the furnace again,

 

let me know

 

Thanks

 

Mark

Customer: replied 7 years ago.
A hose runs from gas regulator up to that box T fitting then hose runs to pie pan then another hose runs from that and just hangs doesnt attach to anything. Blew out hoses and checked fittings. Ran furnace no ignition
Expert:  Mark Henley replied 7 years ago.

Hi,

 

Does the gas valve make any clicking noises at all ?

 

Thanks

 

Mark

Customer: replied 7 years ago.
No
Expert:  Mark Henley replied 7 years ago.

Hi,

 

 

It sounds like a pressure switch problem, the only way to test that for sure is to replace it with a known good one, the other thing you can do is make sure your flue is not blocked or partially blocked.

 

Thanks

 

Mark

Customer: replied 7 years ago.
Flue not blocked. Is switch in gas line ahead of regulator and can I bypass it to test it.
Expert:  Mark Henley replied 7 years ago.

Hi,

 

I don't know if you received my last reply, you can jump it out but its not recommended, you have to jump the two wires out on the pressure switch but you have to do it after the vent motor starts and not before , this is dangerous and I don't recommend doing it.

 

Thanks

 

Mark

Customer: replied 7 years ago.
We live at approx. 1869 ft. elavation, do we need a high altitude pressure switch?
Expert:  Mark Henley replied 7 years ago.

Hi,

 

No,

 

Thanks

 

Mark

Mark Henley and 2 other HVAC Specialists are ready to help you
Customer: replied 7 years ago.
Thanks going to town now to find switch. Will get back to you to let you know if it worked.....
Expert:  Mark Henley replied 7 years ago.

Hi,

 

OK let me know, the question stays open.

 

Thanks

 

Mark

Customer: replied 7 years ago.
Mark had to order the part should have it next week will let you know
Expert:  Mark Henley replied 7 years ago.

Hi,

 

OK, the question will be open on your end , just reply back.

 

Thanks

 

Mark

Customer: replied 7 years ago.
Sorry didnt know you werent paid. I will accept your answer but wont know for sure until order for part comes in. Will let you know. Hope it works.
Expert:  Mark Henley replied 7 years ago.

Hi,

 

No problem, the question stays open still.

 

Thanks

 

Mark

Customer: replied 7 years ago.
Hi Mark, Remember when I told you one of the hoses from pressure switch just hung in furnace not connected. My husband found a place for it to hook to vent fan blower. Everything started working fine. Thanks for your help.
Expert:  Mark Henley replied 7 years ago.

Hi,

 

 

You're welcome,

 

Thanks

 

Mark

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