[robmarx]

Bryant 395CAV furnace. Capacitor outside replace a few years ago. Filter fine. When we kicked on the AC this year, the outside fan runs fine, the copper pipe in the house is cold, the thermostat kicks on the system, but the fan in the updraft blower runs slowly. Checked YouTube and pulled the motor housing to check the ohms (spelling?). Came in fine (fast wire was a lower number than each step down in speed). Fan turns easily using a finger. Fuse is good. Circuit board looks fine front and back. Capacitor on inside blower is not bulging. Cut power and no codes came up. Don't know how to check the relay.

What else should should I be looking at to see why the fan runs slow? Many thanks for any help that can be given.

[ballengerb1]

What was it doing that caused you to replace the capacitor?

[robmarx]

It's been several years, but the outside compressor (was not the fan) just stopped running. Called a repair guy and after troubleshooting replaced the capacitor on the compressor and the AC system has been fine until the inside fan started with its problem yesterday.

[bitters]

Check the voltage on the heat and cool speed on the control board.

[robmarx]

Check the voltage on the heat and cool speed on the control board.

Voltage came in at approx 120 for all except the high speed. That came in at approx 85 volts.

Added - cut power, pulled slow wire, reintroduced power, and the fan ran didn't run (fast wire still connected). Did same for fast wire and the fan ran slow (slow wire still connected. Hope this helps with the diagnostic.

[bitters]

Pull the wires off sec 1 and sec 2 and make sure you have 24V.

[robmarx]

Pull the wires off sec 1 and sec 2 and make sure you have 24V.

27 volts on each.

[bitters]

OK 27v is a good reading. With the stat calling for cooling. Check the voltage on the cool connection and common. You should have 120V.

[robmarx]

OK 27v is a good reading. With the stat calling for cooling. Check the voltage on the cool connection and common. You should have 120V.

Cool (black hi speed) comes back with 120v.

Another update. Running stat on cool, the fan kicks in on slow speed for 5-6 seconds then stops - like its expecting something else to kick in the higher speed. After about a minute the slow fan kicks in for a few seconds only to again stop. It does this a few times. I can feel the cold air as it radiates down from the coils. Feels like sitting in front of an open freezer (reaaaaaly nice given today's temperature).


I have an infrared thermometer and the area around the hub of the motor is between 110 and 130 F.

[bitters]

Try taking the Yellow wire off the "spare" terminal and pull the black wire off the cool terminal. Put the yellow wire on cool.

[robmarx]

Try taking the Yellow wire off the "spare" terminal and pull the black wire off the cool terminal. Put the yellow wire on cool.

It does the same thing as when the black wire was on - runs slow then stops then slow then stops.

edit. I'm beginning to think its the motor. When the motor stops running (in between the session of running slow I described above) the end of the motor (not the hub, but the lattice structure around the hub) gets up to 155 F then cools off while the fan runs, then heats up, etc. like its getting power but instead of running just heats up. Bad smell, too. Like hot electrical. Lee in mind, I'm just an average Joe homeowner, not an HVAC guru, so I'm describing everything like an unskilled, unpaid helper would.

[bitters]

It does the same thing as when the black wire was on - runs slow then stops then slow then stops.

Yea sounds like the motor is going bad.

Let me know if you need help replacing it.

[robmarx]

Yea sounds like the motor is going bad.

Let me know if you need help replacing it.

I reaaaaaaaly appreciate all your help. You, my friend, are a good person. Have a great rest of the weekend. I'll drop a note when I've swapped the motor out.

[bitters]

Thanks for the kind words!