Ruud heatpump fan not spinning


Old 05-13-07, 03:03 PM
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Unhappy Ruud heatpump fan not spinning

The big external fan does not spin when the system is on. The cooling isn't working. Heat seems to work but i only let it run for a minute or two.

I live in phoenix the outside temp is 105 right now.

The question here is does the big external fan need to be spinning all the time or is it one of those it only kicks on when it needs to things. The cooling quit working over night.

The fan motor says A.O. Smith on the side the number following is 323p773 i'm pretty sure that was the number.

I did take the lid off the unit and blow quite a bit of dust out of there. The unit is 12 years old.

If the fan needs to be replaced can i do it myself? How hard is it?

Thanks in advance.
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Old 05-14-07, 08:39 AM
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well i got up there and inspected the fan assembly. I was able to remove it. 4 screws and 3 wires i had to clip, but i made sure i could reconnect them. I took the motor apart after i got it off the roof. It appears the brushes wear wearing on the pickups for quite some time. I'm gonna see if i find a replacement electric motor today and install it, it was a long restless hot night.
Old 05-14-07, 03:03 PM
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ok so i went to an electric motor repair shop and they had a replacement motor in stock. The only difference is the new motor required a 7.5uf capacitor, whereas the older one was 5uf so i bought the new cap and motor and headed home to get the job done.

I found the cap that one of the fan wires was connected to and carefully removed it from the electrical box. I was careful not to touch the terminals (capacitors can carry a charge even though the power is off) and connected the same terminals to the same wires.

Once the cap was back in i set to mounting the new motor and splicing the wires in. The new motor had 4 wires where the old one had only 3. I had the guy at the motor shop show me which one to omit and which wires went to the old colors (brown=brown black=black yellow=orange) I used crimp couplers and then put shrink tubing over the couplers. (you can use a hair dryer to shrink it, I just used my lighter. If you use a lighter be careful not to burn the insulation on the wiring)

i lowering the assembly back into the unit and gave the fan a little spin, it hit a coolant tube so i took it back out and slide the fan blade further down the shaft. Put it back in, gave it a spin and it cleared.

I got off the roof, went to the breaker box and flipped the breaker. It stayed flipped, so that was the first good sign. I set the tstat to cool and the system came on with no snags.

I felt the air coming from the register and it was cooling fast. I went up on the roof and the fan was humming right along.


I only posted incase someone else has this same problem.

Answer: the fan that cools the condenser coils must be spinning if the system is on.
Old 05-14-07, 06:15 PM
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Good on You!!!!!!!!!

Found it, figured it, and fixed it. Good job!

Just so you know, there are units that cycle the fan on and off, or adjust the fan speed with the unit running.

These are more for commercial apps where they need a/c in the winter. But many like trane and crrier are doing this now for residential.

Again, great job!

Wish I could buy you a beer.

Old 05-15-07, 08:35 AM
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The condenser fan motor is a DIY job MOST of the time. You just want to make sure that you get the same HP ,RPM and it turns the same way. With a new capacitor also.

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