Heil FAN outside unit won't start (without my help)...

PaulG10

My friend said this forum was very helpful when his HVAC had issues.

We thought we had the same issue: Fan wouldn't blow unless you spin it manually. So, the AC fan will start up, but it can't do it without my help.

He said his capacitor (see ***) was the issue, and I should change it out. This was his easy fix, so I removed the old one and went to buy a new. Simple fix I thought, so I was relieved.

Now, here's the problem, the old one was still GOOD. It was letting out the correct charge. So, I've since put the old capacitor back in, and I'm back to square one.

***NOTE, I have a dual capacitor 35 UF-370V (3 plug-ins), as well as an oval motor-run capacitor 5 MFD-370V (2 plug-ins). The dual is using the HERM and 'C'ommon plugs, leaving the FAN unused, and the motor-run capacitor is for the FAN (apparently). Both were checked and giving good charges.

Any ideas??

Yoyizit

Did it work with the new cap?
Most cap testers probably do not use the voltage that the cap will see when it is actually connected to the motor, so it's possible a tester will say 'good' but the cap's insulation breaks down when it is hooked to the motor.

Elsewise, it could be a bad connection between the cap and the motor, or a bad motor.

I guess there is a slim chance that there is high resistance in the motor connection, so that when the motor demands high current to start moving, the voltage to the motor drops.
If this were so, the fan's top speed should be slower than normal.

beenthere

Good chance the start winding is bad.

It could be shorted to itself. Or open.

PaulG10

To Yoyizit:
I never actually used a new capacitor. I put the old ones back in, thinking that they were ok. I will go back to purchase them, and hopefully that will work.

Also, with the motor, once I start it manually, it runs at full speed. It does not run slower or lag. Hopefully, the motor is ok then.

To Beenthere:
What could fixing the 'start winding' entail? Any suggestions for researching that as well?

beenthere

Not really repairable.

A motor shop could rewind it. But that will cost you about the same as a new motor. And you wouldn't have any warranty of the rest of the motor.

Yoyizit

At this point I'd say it's a 1/3 chance of a being a bad capacitor, but there's still a small chance it's not the motor.

Since testing is 'free' I guess you could take ohm readings on the motor windings to further narrow down the cause. Somebody on this forum will know typical resistance values for this.

Grainger equivalent motor prices are probably way cheaper than HVAC supply house OEM motor prices.

In any case, save all parts. A lot of perfectly good stuff ends up in the trash due to random parts-changing and misdiagnoses.

HvacWiz

Just repalce the motor with a new capcitor and end it..

Yoyizit

Being 90% certain that a new motor/cap costing $100 will fix it
is equal to being 50% certain that a new $20 cap will fix it.

But, it's not my money riding on this gamble.

When I'm certain, I ask: "Is there any possible way a new motor/cap [or whatever costly component] will not fix this problem?" You'd be surprised at how many more tests you can come up when you ask that question.

COLDIRON

Try replacing the capacitor for the fan motor if that don't work replace the motor after you check all wiring to be sure you are not missing something. It's the cheapest way.

HvacWiz

As he said in his post, the capacitor was already replaced, and this did not correct the issue.

COLDIRON

He did not say he replaced it in his post he said, it was tested and he put it back in.