On Sunday, June 21, 2015 at 10:49:15 PM UTC-4, Tony Hwang wrote:
mcp6453 wrote:
The fan on the outside unit of my heat pump failed. The repair guy replaced the fan with a universal replacement that
was so noisy that it sounded like my generator running. When I finally got them to come back, they replaced the run cap
with a 5uF instead of a 15uF. It made it quieter, and the fan seems to be running normally.

What was original caps. value? You can't reduce the value but you may
increase it some what. With low value cap. the motor may run hotter and
rpm may change.

It's not the original cap's value that's important. It's that the
replacement fan motor is the correct one and that you use the cap
value that is specified for it.

It's not clear what all was replaced. He says the motor crapped out
and the "fan" was replaced and then it was very noisy. Both the fan
and motor were replaced? Just the motor? Most logical thing would be
that only the motor was replaced. In which case, all you have to do
is match the fan voltage, speed, HP and direction and find a replacement condenser
fan motor. And I haven't seen a fan motor where you can change the
cap to whatever you want. The manufacturer specs it and that's what
you use.

If you put a different flan blade in, change the motor to a different
speed and don't know what you're doing, bad things will happen. We
just had another thread here where a genius service guy put in a
1050 RPM, 1/4hp motor to replace a 850, 1/4hp one. So, while the
AC guy claimed it would move more air, the motor is overheating and
shutting down.

Glad once again that I just replaced my own here instead of calling
a "pro".