Blower Won't Come On

Discussion in 'HVAC' started by Bob, Sep 2, 2006.

  1. Sep 2, 2006 #1

    Bob

    Bob

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    I have a Trane XE90 furnace with A/C. The other day the blower just suddenly stopped but the A/C continued to work. On the thermostat I switched to just Fan but still nothing. When I switched to just Heat, the gas ignited but the blower still had no power. I looked at the circuit board and a little red LED light blinks about every second. It seems like the motor is not getting any power. Does anyone know if the problem is either one of the following:

    1) Bad circuit board. Is the blinking light on a Trane XE 90 mean that the board is fine?
    2) Bad capacitator. How do I check to see if it is still good?
    3) Motor is shot. There was no overheated smell when I checked it to see why the blower sunddenly quit. I spun the blower and it spins freely so it is not seized. Could it be a ground wire or any other wire? How do I check to see if power is going to the motor?
    4)Thermostat. Could it be the mechanism that controls the fan is shot? Or is that not possible?

    Your suggestions, if you know or if you've ever experinenced this, would be a great help.

    Thanks.

    Bob
     
  2. Sep 2, 2006 #2

    glennjanie

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    Hi Bob and Welcome to the Forum:
    I'm sorry the heat and a/c companies started using computer boards, they take away all logic.
    A Trane dealer can look in a book and tell you exactly what is wrong by the blinking but most of the rest of us can't.
    Many Trane furnaces and a/c's have direct current motors in order to get the infinite speeds for top efficeincy, which just complicates things even more.
    To check the capacitor; take the capicitor leads off , it has to be discharged by grounding, then put the ohm meter on the leads and it should go from somewhere near 1,000 ohms to zero rather quickly.
    Two out of three problems I have had to troubleshoot were just a loose wire, so check them throughly. Using a volt meter, touch the motor leads where they are plugged into the board one at a time while grounding the other lead, that will tell you if the motor is getting power. Don't touch anything in the thermostat; there is one contact in there that blows the whole thermostat if you touch it.
    The purpose of the board is to get the Trane dealer out to do the troubleshooting for you, for a nominal fee ($50 to $75). Let us know how it works out for you.
    Glenn
     
  3. Sep 4, 2006 #3

    Bob

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    Thanks for getting back Glenn.

    Yea, I hear ya'. The boards throw in a monkey wrench and keeps you guessing.

    Anyway. I checked the leads and they have no power going to the motor. When I turn the power on the board clicks twice, the red light comes on, then clicks another two times and the light starts to flash. A slight electrical buzz is heard coming from the board as if the flow is stuck. The Diagnistic Code for a slow flashing light is NORMAL - NO CALL FOR HEAT. CONTINUOUS ON means REPLACE CONTROL. As per the code it should not be the board but yet no current flows to the motor.

    So, if there is no curret flowing to the motor then that rules out the capacitor and the motor, right? That just leaves the board and the relay. Are the clicking noises acually coming from the board or the relay? Could it be a relay problem that's not kicking in the fan. I checked all the connectors going into the board and none are loose.

    Also, are there places where I can take the relay and board to get tested?

    Look forward to hearing from you!

    Bob
     
  4. Sep 4, 2006 #4

    glennjanie

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    Hey Bob:
    Yes, the relay may be doing the ticking noise. It may even be a micro relay on the board itself. They build in time delays for starting in order to prove the flame or that the compressor is working. If you feel the relay is faulty you could take it off, mark where every wire goes and put a tape label on each wire; take the relay to a supply house and get another like it. They will have 40 or 50 different relays that look very much alike but, if you have the old one they can match it for you. If its afull service supplier they may even test the relay for you. The buzzing noise from the relay means there is a contact inside it that has arced too many times and it needs to be repalced.
    The only way I would think you could get the circut board tested would be by a Trane dealer. I wish you well my friend.
    Glenn
     
  5. Sep 4, 2006 #5

    Bob

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    Thanks Glenn!

    I'll let you know what the problem is once I get the parts tested.

    Bob
     
  6. Sep 5, 2006 #6

    Bob

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    I wasn't able to get the parts tested by anyone after calling around so I decided to to have a tehnician to do a diagnostic. I had earlier considered taking the board off and see if anything behind was burnt but decided to play it safe. Turns out it was the board, there was a small burn mark on the relay. Hindsight's always 20-20.

    Anyone out there know where I can get a new Circuit Board for a Trane XE90? Model #TUC060C936B6.

    Bob
     
  7. Sep 6, 2006 #7

    Hube

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  8. Dec 18, 2008 #8

    brianky

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    I seem to be having a similar problem in that at random times when my furnace is suppose to kick on, I just hear a hum. Nothing else happens. The indicator light is blinking no heat call (slow flash). It seems that when I turn the system off or disconnect the power for a period of time and then turn it on or reconnect the power, it begins to function properly. When it works properly, I can see exhaust coming out the vent outside the house, heat comes through the vents inside the house...etc.

    I have had a service tech come out and he thinks the motor and possibly the fan wheel is going bad. ...keeps mentioning something about bearings heating up (He does not use the term bearing, but I can't remember his exact term.) Says when they heat up, they don't allow the fan wheel to turn and it won't allow the motor to run. He checked the "draw" on the motor and said that it may be a little high, but not much at all. He seemed to be reaching for a solution.

    Before I drop the close to $700 to replace the motor and fan wheel, anyone have any ideas? I figure as long as I can keep getting it to come back on, I will wait until I try to discover a solution. Thanks for any help I can get!

    btw: The same techs just installed a Carrier 2.5 ton heat pump over the summer. They say that portion of the system is working fine. It just seems to be the blower/fan wheel...

    Thanks again!
     
    Last edited: Dec 18, 2008
  9. Dec 18, 2008 #9

    glennjanie

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    Welcome Brian:
    Blower wheels don't just 'go bad', they can only be damaged. The technician was probably talking about bushings in the motor but I would not expect to see bushings in a motor on a Trane unit; more likely ball or roller bearings. Has the motor been oiled? If there is 'not much draw' on the motor, there is no problem with it.
    Let's look at capacitors, board and relays, the more likely problem and a lot less cost.
    Glenn
     
  10. Dec 18, 2008 #10

    glennjanie

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    Hello Brian:
    Just a follow-up, something is not stacking up here. You said you can see exhaust from the vent but later you said the tech had installed a heat pump, apperantly on this same system.
    Is the heat pump a mistake or did they actually install a heat pump to a furnace system? That is really squirlley; perhaps you need to ask for a license. If they can't produce one, call the local inspector.
    Glenn
     
  11. Dec 18, 2008 #11

    brianky

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    HEy...thanks for helping me clarify Glenn. I am definitely learning on the go here. It is my understanding that they installed the heat pump to the furnace. The heat pump does the AC and Heat unless the outdoor temp gets too cold. Then, the gas furnace kicks in. Does that make sense. When I saw the exhaust the gas furnace was running. I had the thermostat set to Emergency Heat so I could see the exhaust...I had physically inspected the flue as much as I could and figure that might be helpful. :)

    The sytem shut down again last night after about 2 hours of normal use...it had only kicked on once in that time. Then, it started with the hum only again. We shut it down for the night by setting the thermostat to off. When we turned the termostat on this morning it came on like normal.

    Thanks again for your help Glenn!

    ps...here is a blurb from the service company that installed the pump...
    http://www.indhvac.com/

    "Carrier's Hybrid Heat™ delivers peace of mind to homeowners concerned about the
    unpredictable nature of utility costs. Hybrid Heat pairs a gas furnace with an electric
    heat pump to provide comfort, economy and flexibility. Your Carrier Hybrid Heat system will automatically switch between electric and gas heating as needed to keep your home comfortable all winter long while optimizing the efficiencies of each fuel source. And, because the heat pump also delivers cool comfort when it's hot outside, your Hybrid Heat system is a complete, year-round indoor comfort solution. Ask your
    Carrier dealer if Hybrid Heat is right for you."
     
    Last edited: Dec 19, 2008
  12. Dec 19, 2008 #12

    glennjanie

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    Hello Brian:
    (As I remove my foot from my mouth)
    So, you have a hybird or dual-fuel heating and air conditioning system; that sounds GREAT! I think there may need to be a little fine tuning of the controls and you'll be fine.
    Glenn
     
  13. Dec 19, 2008 #13

    brianky

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    No worries Glenn! I thought maybe I had really misunderstood something. :) Could you give me an idea of what types of fine tuning may need to be done? I am at the mercy of the repair guys that come out and it would be great if I could understand a bit about what they should try before we just start troubleshooting with expensive parts that I pay for whether they are the fix or not. :) Thanks again for your help!

    btw...I have read a lot about the possibility of the control board going bad. I am thinking that is the board with all the wired plugged in to it. Is there a way to check that to know for sure?
     
  14. Dec 19, 2008 #14

    glennjanie

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    Hello Brian:
    One quick and dirty way to check the board is to look for hot spots, like burned transistors or resistors and charred spots on the backing.
    Glenn
     
  15. Dec 19, 2008 #15

    brianky

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    Thanks Glenn. I had the tech come out again this morning. ...ended up replacing the motor and the fan wheel. He was able to get the fan spinning with the old motor, but had to physically push the wheed to get it going. The motor made sense. I did not understand his reasoning for the fan wheel until I realized that there was a likelihood that he would damage the wheel when removing the motor. He gave a lot of other explanations, but the latter one seemed more realistic. Not sure if that is a normal deal or not, but I went with his advice and replaced both. The company stated that if we did not replace both, that the motor would only be good for 30days rather that a year. :( Oh well...at least we have heat and it seems to be working normally.

    Thanks again for your help Glenn! The piece of mind means a lot!
     

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