Condensor fan speed?

[bundysnake]

Ok so I have a heat pump unit which has 2 speed condensor fans installed although only the high speed is connected, my aim is to reduce the noise created by the fans by using the low speed when suitable.

Has anyone done this? What controls did you use?

[HVACRsaurus]

Will an adjustable HP switch & contractor/relay arrangement to the trick?

[bundysnake]

What about controlling the fans in heat mode? Reverse cycle??

[mad fridgie]

Change your fan speed, change your duty and efficiency. As long as your client know this! and the working pressures remain within an acceptable level then is OK

[cool_tech]

what about a saginomya con fan control?

[alrest]

Saginomiya fan control is a good one to be used. It can be controlled either by the outdoor ambient or modulates according to pressure

[bundysnake]

what about a saginomya con fan control?

Can I wire both fan speeds into this and switches between the 2? As I mentioned low fan wire is currently not used at all.

If the answer to the above question is no then maybe a adjustable HP switch and a relay is the go??

[Tesla]

Hi bundysnake
Whilst in heat mode and ambient is low (12 or less) is usually good to use low speed so a simple relay and tstat control could be used and cost effective to install. This keeps it simple and will help prevent high HP by reducing load on compressor during heating. More complicated control can be used for improved efficiency and noise reduction.
The HP switch is not always best as the indoor coil may be much smaller and when reversed problems are created like flood back.