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 Heath Your Own Question

Heath
Heath, HVAC Technician
Category: HVAC
Satisfied Customers: 1034
Experience:  11 yrs. comm.resid. service, Type III Cert.
Type Your HVAC Question Here...
Heath is online now
A new question is answered every 9 seconds

I have Lennox G26 gas heater. The heater did not kick in when

Customer Question

I have Lennox G26 gas heater. The heater did not kick in when the thermostat temperature is reading lower than the setpoint, say even at 67 when the setpoing is 73.

Is this due to relay board problem?

Thanks
Submitted: 4 years ago.
Category: HVAC
Expert:  Heath replied 4 years ago.
Hello my name is XXXXX XXXXX will be my pleasure to assist you. First thing to check is look in the peep hole in the bottom door to see if the led is flashing a set number of times. Once you check that and record the number of flashes get back to me and we will be better able to diagnose the problem when we know the flash code.
Customer: replied 4 years ago.

Thanks for your reply.

 

Well, the furnace kicks in when the switch for heat is turned down to "off" then "auto".

 

I opened the furnace cover but did not notice any LEDs blinking.

Can you tell me where to look at?

 

We had similar problem before and the lennox technician replaced the johnson control board and it worked for three years.

 

Expert:  Heath replied 4 years ago.
The led should be on the board that they replaced in the lower section of the furnace if you took the bottom door off you will have to hold the door switch in to get any kind of power to the led light.
Customer: replied 4 years ago.

I double checked it. I don't see any LEDs blinking. Is it red colored?

 

by the way, the furnace is 15 years old and the relay controller is "Johnson Control" with model number 63K2401.

Expert:  Heath replied 4 years ago.

Okay maybe this furnace doesn't have a diagnostic led on the board. Is this a standing pilot if so is the pilot lit? What does the furnace do on a call for heat pilot lights but burner never comes on or the burners come on for a second and then shut off?

Customer: replied 4 years ago.

The pilot is lit all the time.

 

Again, the furnace starts when the switch in thermostat is turned to "off" position and back to "auto" position.

 

 

So it seems that burner works.

Expert:  Heath replied 4 years ago.

The problem is probably the high limit tripping or the board like you said before you can verify the high limit is okay if you use an electric meter and ohm the high limit out if it ohms out okay then it is probably good but you will have to check it when the furnace will not work as it is an auto reset so when you turn the thermostat to off and then back on it resets and the furnace will run a cycle till the limit trips again then you will have to reset again. You can also unbend a paper clip pull the wires off the high limit and use the paper clip to jump the wires together and see if the furnace will run more then one cycle if it does the high limit is bad. I am attaching a picture of the limit switch it is usually above the burners in the center area of the furnace.

 

graphic

Customer: replied 4 years ago.

Thanks for your note and sorry for my late reply.

 

(1) The resistance is about 8 ohms from the thermo-resistor, 18J3701-the limit controller. So the limit controller seems OK.

(2) The fan of the furnace started when the wire to the limit controller was pulled out. The fan stopped when the wires were plugged back in.

(3) When the wire is pulled out of the limiter, the fan did not stop even when the switch is turned to "off" position.

(4) I found there is green LED in Johnson controller. But I never see it blinking any time.

 

Is there any way to make the LED blinking?

 

Expert:  Heath replied 4 years ago.
With a fault the light should blink a certain amount of times if it has a diagnostic board. Have you tried jumping the switch out. It may show ohms when you checked it but what about when the furnace will not re-fire after running a cycle? That is when you need to check it as it may trip the high limit to soon or at a lower temperature then it is designed for.

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
< Last | 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:

 
 
 
  • gotoman for ac

    HVAC Technician

    Satisfied Customers:

    4657
    51 years of experience install design and repair of all makes and models of AC
< Last | Next >
  • 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:

    4657
    51 years of experience install design and repair of all makes and models of AC
  • http://ww2.justanswer.com/uploads/AL/alumalite/2012-5-10_234018_shutterstock506249951forJA500.64x64.jpg Phil's Avatar

    Phil

    Mechanical Engineer

    Satisfied Customers:

    3888
    Retired HVAC/ Electrical & Boiler contractor. Industrial
  • http://ww2.justanswer.com/uploads/skibum0101/2008-12-16_015819_just_answer.jpg Rick Mather's Avatar

    Rick Mather

    HVAC Technician

    Satisfied Customers:

    3132
    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:

    1994
    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:

    962
    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