Trane YCX048FM Intermittent Ignition Issue


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Old 10-06-11, 05:04 PM
J
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Trane YCX048FM Intermittent Ignition Issue

Hello
Trane YCX048F1HOA, propane, 4 ton siingle gas/electric unit, outside installation. Early 1993 unit that has been bullet proof for years. A/C side perfect, heater will light sometimes and work fine, other times nothing. I've changed the pressure switch, have 24ACV on both sides of switch with inducer fan tubing installed, thermostat on, inducer motor running. Have cleaned the flame detector sensor. This unit has a 5 jet gas maniflold with the flame sensor mounted on the last burner tube. I can hear the gas valve open, the ignitor lights the first burner, then will either quickly light the other burners (GREAT!) OR the first burner will go out and the unit will cycle and try to light the first burner again after a few minutes. Since the inducer motor spins and the pressure switch has 24 VAC on either side, I'm assuming the inducer motor is creating enough vacuum? I don't have access to a manometer so not really sure. Has always been slow to ignite, 45 sec-2 minutes after T-Stat is turned on. Are there other Safety shut off parts I should be looking at? Any ideas would be greatly appreciated.
John
 
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Old 10-06-11, 06:20 PM
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remove and clean the burners and crossovers.
 
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Old 10-07-11, 09:13 AM
J
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Thanks for your response!
Since I'm not an experienced HVAC tech (but do build muscle cars like you!) can you point me to a place where I can get a Trane IPL that shows the breakdown of the installation of the burners and crossovers? I don't mind taking anything apart as long as I can reference tech data. Not real sure what crossovers are?? Are you referring to the gas manifold/jet tubes in front of the burner tubes or the actual burner tubes themselves?

The burner tubes also have a white divider (asbestos?) in each tube. I was told years ago that by removing those dividers the furnace would work better. It appears that some of this material has deteriorated over the years and pieces might have gone into the tubes.

Thanks again for your help
John
 
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Old 10-07-11, 01:35 PM
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There is no manual that I know of that shows the parts breakdown you requested. The burners (maybe what you call jet tubes?!) have wings on them they are the crossovers and allow the burners to light each other after the first one is lit.

Typical Trane burner......

I would not remove anything...Such as a divider, if it came with it then there is a reason. If you are uncomfortable doing as suggested then I recommend calling a pro.
 
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Old 10-08-11, 11:46 AM
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Thanks for your help Kevin!

I did blow compressed air through these tubes, but will now remove each one and throughly clean. Here is a picture of the white divider tubes I was referring to. I was told they were for emission compliance and the furnance would operate more efficient without them. Leave them alone?

BTW, I have a '65 Chevelle wagon with a BBC. 10 year project, still doing body work

Imageshack - tranehvac002.jpg

Thanks again

John
 
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Old 10-09-11, 05:18 AM
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leave those turbulators alone. While you have the burners out, check the orifices in the manifold to make sure there are no spider webs in them.
 
 

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