Ask Experts Questions for FREE Help !
Ask
    john19990's Avatar
    john19990 Posts: 1, Reputation: 1
    New Member
    		  
    #1

    Nov 26, 2008, 05:29 PM
    Furnace Limit Switch
    I have Bryant upright furnace (Model 394GAW048100). Furnce runs fine for the first 4 or minutes in a cycle and then gas is cut automatically while the pilot is still on. After a few seconds, the gas again comes on and Furnace works fine for about 30 seconds, again gas is cut and so on. I changed the Furnace Limit Switch. Once I changed it, the furnace worked fine without cutting gas for the first about 12 minutes but then started cutting gas for about 30 seconds. A minute on and so on.

    Is it normal for a furnce to cut gas. Or do you know if this is an issue. If issue, what should I check.

    Thanks
    John
    hixton's Avatar
    hixton Posts: 146, Reputation: 5
    Junior Member
    		  
    #2

    Nov 26, 2008, 08:46 PM

    John it could be your firing valve the pick and hold might not be working right give that a try
    MarkwithaK's Avatar
    MarkwithaK Posts: 955, Reputation: 107
    Senior Member
    		  
    #3

    Nov 27, 2008, 06:58 AM

    Ok I'm a little confused here. What is a firing valve? A pick and hold? Never heard these terms.
    hixton's Avatar
    hixton Posts: 146, Reputation: 5
    Junior Member
    		  
    #4

    Nov 27, 2008, 10:16 AM

    The firing valve is the main control that allows gas into the furnace the pick and hold is the way the valve on a bryant furnace works it the way they design it . Troubleshooting should be left to a qualified tech.Firing valves are not cheap.
    MarkwithaK's Avatar
    MarkwithaK Posts: 955, Reputation: 107
    Senior Member
    		  
    #5

    Nov 27, 2008, 11:26 AM

    Odd. In all my years in this industry I have yet to hear that terminology and I'm a Carrier dealer.
    hvac1000's Avatar
    hvac1000 Posts: 14,540, Reputation: 435
    Heating & Air Conditioning Expert
    		  
    #6

    Nov 27, 2008, 01:25 PM
    Quote Originally Posted by MarkwithaK View Post
    Odd. In all my years in this industry I have yet to hear that terminology and I'm a Carrier dealer.
    Example from my class. Used with 3 wire pilot
    Attached Images
     
    hvac1000's Avatar
    hvac1000 Posts: 14,540, Reputation: 435
    Heating & Air Conditioning Expert
    		  
    #7

    Nov 27, 2008, 01:28 PM
    Quote Originally Posted by hvac1000 View Post
    Example from my class. Used with 3 wire pilot

    Pilot
    Attached Images
     
Not your question? Ask your question View similar questions
 

Question Tools Search this Question
Search this Question:

Advanced Search

Add your answer here.


Check out some similar questions!

Furnace Limit Switch [ 15 Answers ]

I've raised this issue in other forums. I have a high efficiency furnace that has worked flawlessly for the last four years (the house was built in 2000). This year we had to have the circuit board replaced. After that there was a problem with the blower, i.e. it wasn't shutting down after the...

Wiring for an older ge furnace fan limit switch [ 1 Answers ]

I have an older ge furnace that I can not figure out the wiring for fan and limit switch. There are 3 wires coming out of the switch. The red one marked limit goes to the 24v trnsformer, the green wire marked fan goes to the furnace sequncer. The other wire is black and unlabeled. Were does this...

Furnace overheats-limit switch kicks in [ 6 Answers ]

I have a Bryant model 376C, induced combustion, gas fired, downflow/horizontal furnace with an overheating problem. Unit is approx 18 yrs old. Limit switch blew, replaced it, and replaced dirty filters and slightly increased blower motor speed. New limit switch also kicks in. Air/return...

Electric furnace limit switch [ 1 Answers ]

HVAC1000. Just to make sure on the switch.What I'm looking at is a two stack six wire switch.Does that sound right?

Limit switch on electric furnace [ 1 Answers ]

Can the thermostat on a limit switch be bad while the rest of the switch is OK?My blower fan works manually but will not function on "auto".

View more questions Search