aire ease furnace wont ignite


  #1  
Old 03-28-05, 04:35 PM
dannyyy
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aire ease furnace wont ignite

I have a johnson air ease ultra sx 80. I went away for 7 days and had the heat turned down to 58 degrees. When I got home I turned the heat up and the blower exaust fan turned on but I dont hear the usual crackling noise from the electric (automatic) ignitor and the furnace wont fire up. I shut it down, thermostat, then gas ,then electric and attempted to resart but still nothing. I looked inside ,I see an ignitor ( like a barbecue) near the pilot gas ttube, an (automatic gas valve ? ),a auto ignition module ( box where thermostat wires seem to run and ignitor to port labeled spark, as well as a circuit board underneath. Ihave never worked on a furnace before but do most of my home repairs.

Any guidance you could offer would be appreciated. Where should I start ? THANK YOU
 
  #2  
Old 03-28-05, 07:04 PM
Harley Landis's Avatar
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Check the air proving switch

You say you don't hear the ignitor "crackling" after the combustion blower comes on.

Typically, a start-up goes in stages. When the thermostat calls for heat, the combustion blower comes on. This effects a diaphram which completes the circuit on a "proving" switch. Once this happens, the gas valve is actuated and the ignitor begins "crackling" until a set number of seconds, or until the burners are lit.

If the ignitor is not working, it may be one of several things. Check the exhaust flue for blockages. Check the air proving switch (it will be near the combustion blower with a rubber hose attached. Make sure the hose is not blocked and is firmly attached. If these things all are working, it may be a bad ignitor. Do you smell any gas after the start cycle?

When checking these things, please make sure the power to the system is off. Safety first!
 
  #3  
Old 03-29-05, 09:57 AM
dannyyy
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gas

does not appear to be any gas going to the pilot and i thought that was a safety featuredue to no ignition spark i will check your suggestions ...further advice appreciated
 
  #4  
Old 03-29-05, 07:51 PM
Harley Landis's Avatar
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Gas valve

I understand your frustration, Dan. During the start cycle, the gas valve and ignitor should come on simultaneously, or nearly so. That's why the ignitor sparks for a set period of time. Then if the flame sensor doesn't send a signal back to the control, the control drops the voltage to the gas valve and it closes. That way the gas is only on for a short time. I hesitate to tell you to get a voltmeter, as I don't know your skill level.

At this point, from what you've told us, the ignitor isn't sparking, so I have no reason to think the gas valve is bad. If you're not getting voltage to the ignitor, then the control isn't sending a signal to the gas valve, either. Something may be wrong before it gets to that part of the start sequence.

On the other hand, if the ignitor itself is bad, and getting voltage but not working, the gas would come on for 7 to 10 seconds and then go off when there is no flame sensed.
 
  #5  
Old 03-30-05, 05:48 AM
dannyyy
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It turns out it was a vacumm hose ....thanks harley
 
 

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