Blower Won't Activate Without Help


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Old 02-28-13, 02:41 PM
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Blower Won't Activate Without Help

Hey there. Got home from work today and noticed it was a little chilly in the house. After a fair amount of fiddling and googling, I've narrowed down the problem but am having difficulty finding the solution.

I set the fan setting to 'On' on the thermostat, but it won't activate either with heat or a/c. I know for sure the furnace is igniting and heard the condenser fire up as well, it's just the blower. I turned the system on and gave the fan a quick spin with my hand and it's working for now.

What should I be checking or does anyone happen to flat out know the solution? The system is a Trane XL80 and can't be more than 5-10 years old. Thanks for any help!
 
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Old 02-28-13, 02:50 PM
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Likely a capacitor. Kinda looks like a small V-8 can slightly squashed. You can Google images for examples.

If it's bulged or leaking anything..it's bad. You need to hurry as you can't buy these just anywhere. Most places that sell them are closed weekends.

Wait for a Pro...but that would be my first thought if it runs with a kick.
 
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Old 02-28-13, 03:55 PM
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The fan has been fine but sounds a little whiney. When I took the cover off it slowed to a stop so will check the return vents and such.

I only saw 3 capacitors, none of which seemed damaged in any way.
 
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Old 03-01-13, 06:57 AM
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Well....if it was running when you took the cover off...you probably tripped the safety switch. Air handlers have a switch that will disable the fan when the cover is removed. You either need to pull out on it or tape it down somehow if you want to operate with the cover off.

Not sure why you would see 3 caps....should just be one somewhere near the blower...
 
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Old 03-01-13, 08:33 AM
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If you trace the wiring from the blower back...I believe the cap is connected to the purple and purple with a stripe wires.

Can you post the model number ?
 
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Old 03-01-13, 01:32 PM
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The safety switch is taped down, it seemed like the fan lost momentum from the loss of air pressure when opening it.

I do in fact see three capacitors, the same three little green guys you see in the image below (found online). Could I be looking at the wrong panel? Also don't see a purple striped wire, just solid colors.

Model number is: 2TXCB025BC3HCAA.


Thanks for the replies!
 
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Old 03-01-13, 01:43 PM
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The cap for the blower won't be on a board. It's too big for that. Should be about the size of a typical pill bottle or so.
 
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Old 03-01-13, 02:09 PM
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Ahh, I found it. Looks alright to me, just a yellow spot on the top near the connections but that looks like it was painted on during production probably.

Is there a way to check it or should I just try a replacement? Any ideas where I might find one?


You were for sure right about trying to get them early, could only find grainger that sells them and they're closed. Will one with a 7.5 mfd instead of the 5 on this one be okay with the same voltage? Trying to get one online and the 5 probably wouldn't get here before tuesday like the 7.5.
 

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Old 03-01-13, 03:06 PM
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So, the fan was running as stated in yesterdays post? You pulled of the cover which set the cover safety switch to open and the fan stopped running? If the switch is taped down (the circuit is closed) and you pulled the cover and the fan seems to slow down, it is because the air supply has increased, causing a greater load on the fan. If the fan runs after spinning it with your hand, it may be the capacitor or the fan motor itself. Do you have to spin it every time to make it run or just some times. Every time, try replacing the capacitor. You will need to remove the old capacitor to ensure you get the correct replacement the voltage and uF numbers should be the same. If you don't have to spin the fan every time, it could be the fan motor. Sometimes they run and sometimes they won't if they get a bad spot in them and will not run unless given a spin. You will need to pull the motor to match it also. Voltage, body size, type, shaft size...
Either way, the part you will need could be found on the internet or at the local HVAC suppy house. The capacitor is a few bucks, the motor 100+. Many of the supply houses will only sell to contractors.
Here is what a capacitor will look like.
 
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Old 03-01-13, 03:26 PM
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The fan runs fine, but only when spun manually. The capacitor appears from the outside to be okay.

Right now I'm just having a problem finding where to buy a new one, and what other causes I could troubleshoot while waiting for Monday to try the replacement.
 
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Old 03-01-13, 03:45 PM
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Well....there's really nothing else to troubleshoot. You need to replace the most likely failed component based on your symptoms and description.

"Looking alright" really requires a well trained eye...and even then they can be bad. The only real test (other than replacement) is a capacitance meter/tester. Caps used to last a long time, but regulations on the chemicals used in construction and the huge influx of foreign made parts, means they just don't last that long anymore.

Call around to any HVAC suppliers or companies in your area. They may be open for limited hours on Sat or a repair company may take pity on you and sell you one for only 200% markup....lol. Plan on about $25-30....though I know you can get them for about $10-12.

You can go higher voltage....but I think the mfd rating needs to be within about 5%? Not sure on that last.
 
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Old 03-01-13, 04:18 PM
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Okay, I'll keep looking locally.

Not sure if this changes anything, but the fan doesn't work 100% of the time it seems. After starting it manually this time, the fan stopped on its own then tripping the limit.

Thanks again for the help.
 
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Old 03-01-13, 05:01 PM
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I would replace the cap and then go from there.
 
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Old 03-01-13, 09:15 PM
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Does it matter which contacts go to which terminal? Both of the wires look the same but I'm not sure if one is supposed to go to a certain side, or position on the terminal. :s
 
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Old 03-01-13, 09:37 PM
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It's an AC part......no polarity.
 
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Old 03-03-13, 04:42 AM
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Grainger's is most places and they will carry your capacitor. You can increase the voltage, but the mfd rating should be kept the same. Your description of the problem is that of a failed capacitor. However, the more you run the motor with the failed capacitor, the more likely you are damaging the windings of the motor.
 
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Old 03-04-13, 01:25 PM
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I figured that would be damaging and stopped trying to run it that way, but maybe that was too late. Just popped in the new capacitor and it still isn't working. When the fan is supposed to kick on I can feel it creeping slowly, but won't speed up even with help.


Also, one more little hypothetical detail to note: say someone was trying to get the fan to kick on several times, and once without the capacitor. Then foolishly tried another time without ensuring the cap wires were secured away from the caps housing, thus allowing one of the wires to hit it with the power on for a brief second and burn a small hole in the wires connector.

Had that happened, in addition to the rest, what kind of damage should I expect?
 
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Old 03-04-13, 01:30 PM
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Time for a new motor.....
 
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Old 03-04-13, 01:49 PM
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"Also, one more little hypothetical detail"
Lol.....it's ok...you can admit it. Even the Pro's have made mistakes....how else do you learn?

btw...a motor going bad can eat a cap...or a bad cap can cause a motor to fail. Any time you replace a motor...you should replace the cap as well...so you aren't out anything other than time.
 
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Old 03-05-13, 01:27 PM
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When I was buying the capacitor one of the techs asked if I had "wrung out the cap to make sure that's it". I asked what he meant and he wasn't very divulging, anyone know what that is?

Also I noticed a sign about motor testing there. Is that just them using a multitester on it? Is it usually even worth rebuilding the motor instead of buying a new one?
 
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Old 03-05-13, 07:18 PM
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wrung out the cap...... I like that. And you responded... yes and now it's hanging on the clothes line.

You can use a regular ohmmeter to check a capacitor. Set your meter to Rx1 ...touch the leads to the capacitors for a few seconds. Now reverse them. The meter should swing up and then come down slowly. You can also try it on the Rx10 scale. Not a particularly accurate way to determine the condition of a cap.

As far as rebuilding the motor...... it's not cost effective. With the price of labor it would cost you hundreds of dollars to rebuild a small motor. Most fractional size motors are replaced. When you get over several HP it can become more effective to rebuild.
 
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Old 03-28-13, 03:28 PM
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Hello again! So for whatever reason I've put off pulling the motor and replacing it till now and while looking up any tutorials I can find, I've come across a few more questions.

I asked this before but just to double check as one tutorial explicitly mentioned to make note of this, do the cap wires need to be in the same location they were on the previous cap? ie: there are two terminals and four connections on each, do the wires need to be reconnected to the exact same position or terminal as they were on the previous cap? Sorry to reiterate, just don't want to blow another motor or cap!

Do I for sure have to pull the entire motor before I can find the replacement? Would like to have it on hand to compare before I start yanking wires off if possible, but read somewhere that with a gas furnace you're not supposed to leave it sitting with the power cut off for long (which puzzles me).

Also any little tidbits of advice or suggestions will be greatly appreciated! I can build a computer no problem, but just looking once at the diagram for the motor makes me highly paranoid...
 
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Old 03-28-13, 07:46 PM
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Turn the breaker off. It doesn't matter which spade you put the wire/wires on. If there are two wires on the same terminal make sure they remain together. If you have the make and model of your unit, you should be able to get the proper motor before you pull the old motor. Do you still have the owners manual? You may have a parts list. If you leave a gas furnace with the power turned off for too long, the problem is, your house will get cold.
 
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Old 03-29-13, 07:15 AM
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Haha, thanks. Pulled the motor out and looking up replacements now. This motor is 1/3 HP, 115 V, 1075/4 SPD, 5.8 A, 60 Hz. However, I can't seem to find a perfect replacement. Either the amperage is off, or it's not a 4 speed. Do I really need a 4 speed or will a 3 speed work? If so, what should I do with the wires?

Also where am I supposed to be seeing the frame size? Can't find it anywhere on here.
 
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Old 03-29-13, 10:22 AM
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its likely a 48 frame. Amperage can be higher, but not lower than the original. 3 speed will work, but I recommend 4 speed.
 
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Old 03-29-13, 12:08 PM
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Picked up the 4 speed from Grainger. EDIT: The motor is mounted and fan wheel fits and spins perfectly (and barely fits in the enclosure)!
 

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Old 03-29-13, 03:13 PM
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Alrighty, got everything back in place, fired it up and the blower won't accelerate past medium or low, whatever speed it is at. Thus tripping the limit switch and giving a no call for heat error.

What could this be? I thought for sure I had the new colors matched right..


Doh! After thoroughly double-checking my work on the wiring, I realized that I have no clue which way clockwise is when facing the motor! I had checked to make sure the polarity switch on the motor was set to CCW many, many times before starting it up, only to find out now that it was supposed to be CW!

Thanks so much for everyone's help! I finally have heat (now that spring is here, at last)! :No Beer 4U:
 

Last edited by asdf_msc; 03-29-13 at 03:29 PM.
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Old 03-29-13, 03:32 PM
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Check your fan rotation. Universal motors can be set for clockwise or counter clockwise rotation.

Never mind, I see that you've got it.
 
 

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