condenser fan control

[rookietech]

Is it important to cycle a condenser fan motor on the liquid pressure control on a water chiller? or can the fan cycle on and off with the piston type compressor? The outside ambient temp rarely drops below 40 degrees F

[Brian_UK]

A liquid pressure control would be better. A variable speed device even better than that.

[Greengrocer]

Depends on the size / capacity of the chiller and the application. On larger air cooled water chillers with multiple fans (4/6 or more) a combination of on/off fan cycling & fan speed control is often used. The variable fan speed control would be used in conjunction with the last step / stage of cooling. All would be linked to the step / stage control of the compressors / circuits & all would depend on the min % duty required against the minimum operational ambient temp.
On smaller chillers with limited or no steps of capacity control and only one or two fans, fan speed control of one or both fans would normally be required if operation at lower ambient temperatures is expected. Manufacturers should be able to state what the minimum operational ambient is for the standard machine at full & part load capacity. Also whether any accessory HP / fan control is available as an accessory. Same applies for condensing units.

[rookietech]

Thanks greengrocer, makes troubleshooting alot easier