Trane xv90 issues


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Old 11-04-10, 10:52 PM
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Trane xv90 issues

I have a Trane XV90 furnace I am having issues with. Typically I turn off the unit during summer and start in autumn. This year when I went to start it I got all I got was an “inducer fault” as per the blinking diagnostic light. Everything else seemed to work and I was getting 123 volts to the inducer itself (fasco A190 with the little circuit board connected). Bearings were less that smooth and with a little work (cleaning and silicone lube) I was able to get it to spin at times. The best I was able to do would be to get the furnace to ignite one jet and then go out. After it would go out it would give the three flash “inducer fault” on the diagnostic light. At one point in the aggravation when this happened I grabbed a pair of pliers to try to help the motor spin (I had the back end exposed) and I got some pretty stiff fireworks. I must have contacted the small board with the pliers and fried something.
I was sure I knew what the problem was so I ordered a new inducer motor and installed it yesterday. Now I have nothing. No voltage to the inducer and I get the three flash inducer light quickly after turn on. Did I do some really bad damage to the main control board? I am getting rather scared about now!
The sparks were from the little board on the back of the inducer motor and not the main control panel. Other information that might be important:
The thermostat was replaced at the beginning of the issues and is calling for heat (as per the diagnostic led).
The inducer limit switch (normally closed as per the schematic on the back of the panel) has been bypassed.
The little 5 amp auto type fuse is good.
The two pressure sensors seem to be functioning properly and they are routed to the inducer itself, not the control board.
The unit is calling for heat (fast flashing led) when turned on, then cycles out and gives the three flash “inducer fault”.
I was getting voltage to the inducer before the sparks, now I am not.
Between the time of sparks until the new motor was installed was over 48 hours and the power was turned off to the unit at the circuit breaker on the house SE.
The control board is a cnt02536 50a61 White Rodgers.
Does anyone have any guesses of what I might be up against? Any troubleshooting ideas? Any help would be truly appreciated. Earl.
 
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Old 11-05-10, 11:18 AM
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inducer turning!

This pic is of the new inducer motor and placement in the unit, it’s now working! Well almost. It had a bad connection to the control panel. Now when turned on the unit goes thru its proper motion but after the jets light they almost immediately extinguish. Everything seems to be reconnected as before. It cycles a couple times then I get the two flash diagnostic light telling me it cycled out. I don’t hear the pressure switches clicking and the ignition appears to be strong. Anyone have any ideas? I sure could use some help here. Earl.

 
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Old 11-05-10, 05:53 PM
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Does a glow coil or does a pilot light the burners? If glow coil (HSI -hot surface ignitor), clean the flame sensor rod that is located on opposite end of burners from glow coil. Also clean any cross-over tube between burners of possible spiders/nesting/debris. If a pilot system, you may have to remove entire pilot assembly to polish any metal the pilot flame strikes, to create the ground-sense circuit, and also clean pilot orifice while at it.
 
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Old 11-06-10, 05:40 AM
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Thanks ecman51!

thanks for the reply,Not sure what the problem was but after all the effort I put in it my wife came down and flipped the switch and it fired up! Guess it either took a womans touch or just needed a few more cycles to purge the gas. Earl.
 
 

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