Pretty sure that the capacitor on my AC blower unit has failed - 5uF 440vac oval shape. I think I can find the part on Amazon, but any suggestions for brick and mortar locations in Houston that carry these parts and sell retail?

I looked all over. Ended up buying from my BIL who owns/maintains several rentals. Come to find out, he buys online too. But we are in rural north Texas.

Maybe talk to a servicer in your area if you know one on where they get their parts if your trying to stick with brick and mortar.

I called hvac companies until I found a guy who'd sell me one

I have had luck buying from Johnstone Supply.

Thanks Ags. Unfortunately, I tested the capacitor this morning and it appears to be good. So back to the diagnosis drawing board.

PetroAg87 said:

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Thanks Ags. Unfortunately, I tested the capacitor this morning and it appears to be good. So back to the diagnosis drawing board.

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What are the symptoms?

johnson supply

Brad06ag said:

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PetroAg87 said:

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Thanks Ags. Unfortunately, I tested the capacitor this morning and it appears to be good. So back to the diagnosis drawing board.

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What are the symptoms?

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Noticed last week that the AC wasn't blowing air out of the vents. Outside compressor was working fine and it appears that the refrigerant was circulating through the pipes. However blower in the attic unit wasn't turning on. I noticed the same thing when we turned the heater on this week. Furnace fires up but no blower to move the air.

When turned on, the blower will make a humming sound most of the time. A few times, it is more or less silent. I suspected the capacitor, but put a multimeter on it and it tested fine. I wish I could spin the blower blades by hand and see if I can get it started that way, but the blower configuration keeps me from access the blades unless I remove the blower unit first. If capacitor is working OK, my next thought is that it might be the blower motor itself that has gone bad.

Sounds like the start capacitor on blower motor or blower motor. Check the transformer to make sure it is working and not bad.

I'm thinking the same thing. Checked the start capacitor and it checks out as OK. I might put the multimeter on the transformer and double check the connections. But the fact that the fan doesn't blow with either AC or heat makes me think the motor is the most likely issue, since there is a different wire and connection for AC blower and heat blower. Replacing that is unfortunately a bit beyond my skill set and at this point, I'll likely be calling in an expert.

Thanks for the advice and info.

If transformer is not putting out correct voltage that could shut it all down.

I bought spares on Amazon.

Petro,

Usually a 'hum' coming from a single phase motor means either the capacitor is shot/weak, or the motor is locked or jammed. Sometimes a cowling can come in contact with the wheel and keep it from starting.

I assume you used a digital VOM to check capacitance and you got the 5uH. If you just checked resistance, it may be time to check again.

Sometimes you didn't hear the hum, and that may be because the motor kicked out on the overload and needed time to reset itself.

If possible, try to stick something in the blower wheel (power OFF) and try to spin it.

One other thing -- the turning off/turning on of the blower fan (at least on conventional units) is via a 'Sequencer', which is really nothing more than a time-delay relay with the 24 volt transformer voltage from the thermostat controlling it.

When these go bad, the fan never gets juice. Since you've heard a hum, that's probably not it, but I threw it in for good measure. I've replaced several over the years.

TLDR - make sure the capacitor is within spec -- make sure the wheel isn't jammed.

Ferguson will sell retail.

There is a Ferguson Heating and Cooling location at Beltway 8 and Hwy 290. Street address is 10515 Okanella St, Ste 200. Phone is 713 466 1395. Think they are only open M-F.

There is another location down in League City if that helps.

Good luck.

Ace hardware has a limited selection if the aforementioned supply houses are closed.