# Blower Fan Short Cycling ... Please Help!



## zappa (Nov 25, 2011)

The thermal overload inside of the blower motor sounds like it's opening. Bearings, check that the blower wheel spins freely, with the power off so it doesn't start unexpectedly. Run capacitor, check the microfarad value or just replace if you can't measure it. Motor, might need to be replaced.

When you touch the motor is will be warm but shouldn't be burning hot.


----------



## RealestWhiteBoy (May 8, 2015)

Thanks so much for your reply.

When the motor short cycles, I have let it go 2 or 3 times of starting and stopping and then touched the motor, and it's not even warm. It sits in the middle of the fan, I haven't reached my hand back and touched it within there ... I just touched the end of the casing. Should I run it and touch it deeper within the fan when it short cycles?

The fan spins with no effort at all when I touch it, and I don't hear any noises when spinning it by hand. Also, so stray/unusual noises when the motor is spinning it.

I have a 7 function digital multimeter that I've tested the thermastat with and it's giving me a spot on reading. However, it doesn't have a capacitance setting, I'm assuming I'd need a capacitance setting to check the microfarad?


----------



## Mr.HVAC (Jan 1, 2010)

Yes, you do need a meter that reads microfarad. Based on what you describe. I am %80 sure it is the capacitor. You might want to try that first since it is cheap. Just make sure you get the right one. On your old Capacitor, look for something like 5uf, 7,5uf, 10uf, ect. <--- is the size of the capictor you want to get. here is a picture of the capacitor http://www.zoro.com/proline-motor-r...Ne-xgJwVZUGyoIjrjgNnuRoCeAzw_wcB&gclsrc=aw.ds

NOTE: MAKE SURE YOU TURN OFF ALL POWER TO THE FURNACE BEFORE ATTEMPTING TO REMOVE/INSTALL THE CAPACITOR!!!!!!!!!!!!!


----------



## RealestWhiteBoy (May 8, 2015)

It's a 5UF/370VAC 60HZ by CSC

There's a Grainger's 20 min from my house and have the part for $6 in stock, but don't open until Monday at 8am. :/

I talked to a certified hvac that's a friend of a friend. Using pictures I sent of my system and setup, he walked me through bypassing everything and straight wiring the motor to the power supply. The problem still existed. So, we were able to limit the options to either the motor itself or the capacitor, and he said that because it starts so easy, his gut was that it isn't the capacitor. We let it go for 3 or 4 cycles, and after that the motor was pretty hot. I wasn't able to touch it for more than a second or two, and it stayed warm to the touch 30 min later. So, it does seem to be overheating.

He said a new replacement could be anywhere $300-500 parts and labor. If I can find a small engine shop to work on it, maybe $50 to rebuilt. I looked at Graingers and similar direct-drive motors are $100-200. I would prefer to DIY by buying the new motor ... the only concern I'd have is matching up the specs. I assume they'd need to match exactly.


----------



## Mr.HVAC (Jan 1, 2010)

possible a motor also, but I would try to replace the capacitor first. even if you have to replace the motor, you still need a new capacitor with it. If grainger is closed, you might want to try johnston supply. I don't know if they will sell to public in your area. Just do a google search for johnston supply in your area. As far as rebuilting the motor, I wouldn't wasting time, labor, money on the rebuilt. I can be wrong, but I think johnston supply is also the distributor for thermo pride, you might want to ask them on that. If they are, all they need is the model and serial # of the unit. I doubt it that they will sell you a new motor due to liability reasons. But it wouldn't hurt to ask.


----------



## zappa (Nov 25, 2011)

hnguyen11033 said:


> possible a motor also, but I would try to replace the capacitor first. even if you have to replace the motor, you still need a new capacitor with it. If grainger is closed, you might want to try johnston supply. I don't know if they will sell to public in your area. Just do a google search for johnston supply in your area. As far as rebuilting the motor, I wouldn't wasting time, labor, money on the rebuilt. I can be wrong, but I think johnston supply is also the distributor for thermo pride, you might want to ask them on that. If they are, all they need is the model and serial # of the unit. I doubt it that they will sell you a new motor due to liability reasons. But it wouldn't hurt to ask.


Agree 100%. You may want to buy a capacitor based on the replacement motor that you choose but not yet purchased. Sometimes there is a small difference in value but it should be close enough to check out your original motor.


----------



## WyrTwister (Jul 22, 2013)

Our Johnstone Supply is open Saturday morning .

If you have a shop that repairs motors , check them .

But here is the deal , running the A/C like you are is most likely not a good thing . I would be concerned that if the suction line at then condenser is icing up , you may have liquid refrigerant returning to the compressor ? I have read this is not good , liquid does not compress very well .

God bless
Wyr


----------



## RealestWhiteBoy (May 8, 2015)

I'm not running it, only when testing/checking something. It's been off for 4 days, now. I took it back to the 90's ... got 2 oscillating fans. 

This is the Johnson Supply you guys are talking about: www.johnsonsupply.com/ ?

If so, it looks like there isn't one near me. Mostly Texas locations ... I'm in NC. :/


----------



## old_squid (Oct 31, 2012)

Johnstonesupply


----------



## WyrTwister (Jul 22, 2013)

Yes .

Johnstonesupply.com Not johnsonsupply .com .

God bless
Wyr


----------



## nap (Dec 4, 2007)

WyrTwister said:


> Yes .
> 
> Johnstonesupply.com Not johnsonsupply .com .
> 
> ...


I don't know if it is the same nationally but our local Johnstones do not sell retail so unless the OP has some sort of business license where Johnstone wouldn't have to charge sales tax they could not sell to the OP. 


In fact I think Grainger does not sell retail either if I remember correctly.


----------



## nap (Dec 4, 2007)

RealestWhiteBoy said:


> It's a 5UF/370VAC 60HZ by CSC
> 
> There's a Grainger's 20 min from my house and have the part for $6 in stock, but don't open until Monday at 8am. :/
> 
> ...


----------



## RealestWhiteBoy (May 8, 2015)

Graingers around here sells to the public, but I do have a computer and web development business. With Grainger their rep said I could set up an account with them with my web development business. However, with Johnstone Supply, they ask for a contractor license ... so, I don't think I could buy from them.

Grainger warranty GREATLY varies based on if you have a business account. 30 days return for an unopened product as an individual customer, 1 year warranty for business account purchases.

The Grainger rep recommended this motor: http://www.grainger.com/product/4KA28?cm_sp=HIO-_-Home-_-VTV70300505&cm_vc=HPPVZ11&zoneId=HPBTZ11

Any thoughts? They carry the brands Dayton, Century, Genteq, Marathon. Dayton is the "Grainger Choice" brand and $15-20 cheaper ... is any one brand better than the other? I know Century is a brand I recognize, as someone who knows nothing about HVAC. So, I assumed it was the more "name brand", but does that really make it better?

Also, since it has a return and I'm in the area a couple times a month, I decided to go ahead and buy the motor and capacitor. When I get home, I will try the new capacitor. If it fixes the issue, then I can always return the motor next time I'm in the area.


----------



## RealestWhiteBoy (May 8, 2015)

I got my motor today. Reassembling everything right now, just got one more question, anyone know what are these silver rings that came with the motor:

















http://tinypic.com/view.php?pic=ztw6dt&s=8

It has 1 of these on each end of the motor and 4 spares. The motor I took out doesn't have these (those it has an indention on either end of the motor where they'd easily fit). I was going to take them off the new one, since they weren't on the old ... but since there are spares, it makes me think I should leave them on?


----------



## beenthere (Oct 11, 2008)

Hub mount rings. Not needed if your not hub mounting the motor.


----------



## RealestWhiteBoy (May 8, 2015)

Ah, thanks. I recon it's safe to leave the ones the factory attached.


----------



## RealestWhiteBoy (May 8, 2015)

Got everything hooked up, just want to clarify if I'm reading my wire diagram correctly before I put power to it.










Obviously, brown and brown/white wires go on my capacitor. Also, my black and red go on my high and low connections (my last motor was 4 speed, but only utilized 2 speeds). So, no problems here.

My question is coming in because the motor has no WHITE wire, but has a YELLOW wire. Am I reading the wire diagram correctly that yellow is my neutral? I'm under the assumption that it has to have a neutral? And yellow is the only wire left?


----------



## WyrTwister (Jul 22, 2013)

Yellow = neutral . That would be my interpenetration . If it is 120 VAC , it needs a neutral .

Do not forget to verify rotation .

God bless
Wyr


----------



## RealestWhiteBoy (May 8, 2015)

Yea, it's well over that (370vac). So, yellow is all that could be neutral, as far as I can see.

My previous motor only had 1 rotation. Is there a way to know which way it'll spin before cutting on power? My plan was to cut it on, and if it was spinning wrong to cut power and flip the rotation?


----------



## zappa (Nov 25, 2011)

RealestWhiteBoy said:


> Yea, it's well over that (370vac). So, yellow is all that could be neutral, as far as I can see.
> 
> My previous motor only had 1 rotation. Is there a way to know which way it'll spin before cutting on power? My plan was to cut it on, and if it was spinning wrong to cut power and flip the rotation?


It's a 120 volt motor according to your link, 370vac is what the capacitor is rated for.

Do you know which way the blower is supposed to turn? CCWLE= counter clock wise looking from the lead (wire) end of the motor. CW is the other direction obviously. Look and see which way your wires are connected and that will tell you which way it is going to spin.

Be careful if you forgot which way the blower is supposed to turn. It will move air in the right direction spinning both ways but going in the wrong direction the air movement will be much less than needed.


----------



## RealestWhiteBoy (May 8, 2015)

Ah, ok. Yea, it says 115v on the name plate, then also says 370vac (I guess that was for the cap rating that it needed).

It came set up to spin the fan CCW, and that's the correct way.  I have air, and my house will soon be under 80 degrees.  Woooo!


----------



## zappa (Nov 25, 2011)

Good job....did you do any checking to see if it was the cap or motor?


----------



## RealestWhiteBoy (May 8, 2015)

I didn't. The new cap was a 10, rather than 5. So, I wasn't sure if it was a good thing to hook it to a motor that asked for a 5.

But I wasn't feeling like dragging it all out and putting the new motor in if it didn't work. hahaha Was feeling lazy today. But I have a buddy with a meter to check the cap, so I was going to pack it over his way to test it next time I see him.


----------



## WyrTwister (Jul 22, 2013)

Congrats ! 

God bless
Wyr


----------

