How JustAnswer Works:

  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.

Ask HVAC Guru Your Own Question

HVAC Guru
HVAC Guru, HVAC TECH
Category: HVAC
Satisfied Customers: 7533
Experience:  15yrs in the HVAC industry with certificates and degrees.
21107370
Type Your HVAC Question Here...
HVAC Guru is online now
A new question is answered every 9 seconds

Furnace thermostat will not turn on the heat.

Resolved Question:

My furnace won't start when the thermostat calls for heat. The draft inducer motor never stops. I can get the ignitor to start by shutting off the power for a few seconds. When I do that (power off then back on) the ignitor glows, the gas comes on and the furnace runs normally until the next time heat is called for.

Submitted: 2 years ago.
Category: HVAC
Expert:  HVAC Guru replied 2 years ago.
Have you watched it when it calls for heat the next time to see if it tries to light again? Does the ingitor come on the second time?
Customer: replied 2 years ago.

I have not tried that. It is running now so I will have to wait until it stops at 72 degrees. And then find somebody to turn the thermostat up while I watch it in the basement.

Expert:  HVAC Guru replied 2 years ago.

Yes do that and get back to me.

Customer: replied 2 years ago.

Your tester won’t work because the thermostat has already called for heat and failed before I crank up the temperature to look for a start. My thermostat is set at 72. The temperature went down to 70 when we tried your test by turning it up to 75. It did not start until I turned the power off and then on again. I think what I would have to do is set the thermostat to a low number where the room temperature is much higher and then try your test again. If that is correct, let me know and I will do it that way.

Expert:  HVAC Guru replied 2 years ago.
You may have an issue with the thermostat itself. Make sure the batteries are replaced on the thermostat. Also you can take the thermostat off the wall so you can see wires. If it is not starting, twist RH and the W wires together when it does not start or jump the wires at the terminals with a paperclip. See if it comes on. If the furnace starts up just fine I would say you have a bad thermostat.
Customer: replied 2 years ago.

With the room temp over 73 we turned the stat down to 55 to make sure it was off. With me watching the furnace and my assistant turning the temperature of the thermostat up to 85 there was no start or attempted start. I did my usual by turning off the power to get a start, which worked as usual. The thermostat test above I don’t think I will be able to do until tomorrow. Let me know if the above test requires the thermostat test.

Expert:  HVAC Guru replied 2 years ago.
Yes I believe you have a thermostat problem. You have to manually jump the wires at the thermostat or at the furnace board. If it starts up you have a thermostat issue.
Customer: replied 2 years ago.

I have changed the batteries in the stat and will try jumping the terminals tomorrow. I will report to you then.

Expert:  HVAC Guru replied 2 years ago.
Ok great!
Customer: replied 2 years ago.

Okay will do the jump test tomorrow. Meanwhile think about how the water drain line to the sewer would affect our problem if clogged.

Expert:  HVAC Guru replied 2 years ago.

It should not unless you have a condensate sensor that has been activated by the back up in water. Normally it would never come on though. One of the other good techs on here brought up a great point. If the inducer motor is never shutting off, then it will never be able to call for heat again. If that is the case, then the relay on the control board is bad and stuck closed for the inducer motor.

Customer: replied 2 years ago.

My thermostat has terminals RC (red wire) and W (white wire) I assume you wanted me to jump the red and white wire. I did jump the red and white, which had no effect. While holding the jumper in place I tried my power off and back on trick and got a re-start. As soon as it started I pulled the jumper and the furnace shut down. Meanwhile, the inducer motor keeps running. Is the inducer motor relay soldered to the board or is it a plug-in relay?

Expert:  HVAC Guru replied 2 years ago.
The inducer relay would be part of the board. If that is happening you will need to replace the board. That for sure is the issue here.
Customer: replied 2 years ago.

You are 100% sure it is the board?

Expert:  HVAC Guru replied 2 years ago.
Yes it is the board.
Customer: replied 2 years ago.

Okay, I am on my way to pick up the $165.00 board. Will report back to you after it is installed.

Expert:  HVAC Guru replied 2 years ago.

Ok no problem.

Customer: replied 2 years ago.

The board is replaced and everything seems to be working, I will confirm after a few more cycles.

Expert:  HVAC Guru replied 2 years ago.

OK GREAT!

HVAC Guru, HVAC TECH
Category: HVAC
Satisfied Customers: 7533
Experience: 15yrs in the HVAC industry with certificates and degrees.
HVAC Guru and other HVAC Specialists are ready to help you

JustAnswer in the News:

 
 
 
Ask-a-doc Web sites: If you've got a quick question, you can try to get an answer from sites that say they have various specialists on hand to give quick answers... Justanswer.com.
JustAnswer.com...has seen a spike since October in legal questions from readers about layoffs, unemployment and severance.
Web sites like justanswer.com/legal
...leave nothing to chance.
Traffic on JustAnswer rose 14 percent...and had nearly 400,000 page views in 30 days...inquiries related to stress, high blood pressure, drinking and heart pain jumped 33 percent.
Tory Johnson, GMA Workplace Contributor, discusses work-from-home jobs, such as JustAnswer in which verified Experts answer people’s questions.
I will tell you that...the things you have to go through to be an Expert are quite rigorous.
 
 
 

What Customers are Saying:

 
 
 
  • You did one super job of explaining to me everything there is to know about this fridge. I'm looking forward to asking you questions in the future. Jimmy Bagley, IA
< Previous | Next >
  • You did one super job of explaining to me everything there is to know about this fridge. I'm looking forward to asking you questions in the future. Jimmy Bagley, IA
  • Wonderful service, prompt, efficient, and accurate. Couldn't have asked for more. I cannot thank you enough for your help. Mary C. Freshfield, Liverpool, UK
  • This expert is wonderful. They truly know what they are talking about, and they actually care about you. They really helped put my nerves at ease. Thank you so much!!!! Alex Los Angeles, CA
  • Thank you for all your help. It is nice to know that this service is here for people like myself, who need answers fast and are not sure who to consult. GP Hesperia, CA
  • I couldn't be more satisfied! This is the site I will always come to when I need a second opinion. Justin Kernersville, NC
  • Just let me say that this encounter has been entirely professional and most helpful. I liked that I could ask additional questions and get answered in a very short turn around. Esther Woodstock, NY
  • Thank you so much for taking your time and knowledge to support my concerns. Not only did you answer my questions, you even took it a step further with replying with more pertinent information I needed to know. Robin Elkton, Maryland
 
 
 

Meet The Experts:

 
 
 
  • Phil

    Mechanical Engineer

    Satisfied Customers:

    4916
    Retired HVAC/ Electrical & Boiler contractor. Industrial
< Last | Next >
  • http://ww2.justanswer.com/uploads/AL/alumalite/2012-5-10_234018_shutterstock506249951forJA500.64x64.jpg Phil's Avatar

    Phil

    Mechanical Engineer

    Satisfied Customers:

    4916
    Retired HVAC/ Electrical & Boiler contractor. Industrial
  • http://ww2.justanswer.com/uploads/SE/ServiceTechRus/2012-6-7_2119_056.64x64.JPG gotoman for ac's Avatar

    gotoman for ac

    HVAC Technician

    Satisfied Customers:

    4916
    51 years of experience install design and repair of all makes and models of AC
  • http://ww2.justanswer.com/uploads/skibum0101/2008-12-16_015819_just_answer.jpg Rick Mather's Avatar

    Rick Mather

    HVAC Technician

    Satisfied Customers:

    3133
    35 years experience, HVAC
  • http://ww2.justanswer.com/uploads/RY/Rygis20/2011-5-7_3143_DSC5324.64x64.JPG Matthew's Avatar

    Matthew

    HVAC Technician

    Satisfied Customers:

    2014
    14 years experience in the HVAC field of service, installation, Manual J & D calculations
  • http://ww2.justanswer.com/uploads/KE/kentguidry/2011-9-26_214316_0059.64x64.jpg Kenton Guidry's Avatar

    Kenton Guidry

    HVAC Technician

    Satisfied Customers:

    963
    12 years install/service experience.
  • http://ww2.justanswer.com/uploads/solarman1947/2009-12-13_223915_phpkKBcXq_c2PM.jpg Rick Ridley's Avatar

    Rick Ridley

    UK Heating Engineer

    Satisfied Customers:

    871
    Retired But have had 30 years on the tools, Ex CORGI
  • http://ww2.justanswer.com/uploads/Ironheadfan/2009-12-18_222416_pump_005.jpg Tom's Avatar

    Tom

    HVAC Technician

    Satisfied Customers:

    770
    16+yrs HVAC/R service. Residential Commerical Industrial