Heat pump groans when starting

[robsin]

I have a Bryant heat pump outside and a carrier air handler in the attic.
(Not sure the sizes, but I DO know the outside unit is a ** or a *** type as
opposed to some other type. My installer said it was "better" than the other type,
whatever that is).
Anyway, it has been in for 2 years now and about 2 months ago (late *), the heat pump began
to GROAN quite loudly when it starts up. Other than that, everything seems OK.
Is this a * Should I get this * I DID talk to the installing company and
he said "sometimes when its cold that can happen" and didn't seem too concerned, but
I'm skeptical.
*

Thanks,
Rob

[robsin]

The groan is a 2 pitch GROAN, High/low lasting about 1 to 2 seconds when the outdoor condensing unit kicks in . Only noticed in the past 2 months (winter).
The unit is a Bryant Model 265A.
Thanks for any thoughts.

[nomadpeo]

sounds like you are possibly describing a sound that can occur when a reversing valve changes position. if this is the case, it may be normal for you to hear a sound like that when pressures equalize in the system. the fact that it has been happening within the last couple months coincides with the heating season. do you hear it outside when the unit turns off *

[robsin]

Not consistently (on Either startup or shutdown), however, I believe we hear it occasionally on shutdown, as well, just not as loud.
Is this a "*" Does something need *
Thanks

[nomadpeo]

does not sound like a problem. if it was, you would probably notice a performance problem as well.

one possible is a loose rainshield, sometimes referred to as a slinger. it is a plastic piece mounted on the shaft of the motor between teh motor and blade. it was used a lot on older units to help keep rain out of the motor bearing. if it gets loose, it may slip on the shaft and make a racket. if it is a motor bearing, the only fix is a new motor.