Three Phase Head Pressure Control
The 865D-2 low ambient three phase head pressure control monitors the head pressure by sensing excessive liquid sub cooling and modulates the condenser fan motor speed and varies the volume of air through the condenser. Each application requires the controller be installed as a package with a continuously variable speed High Slip tolerant/ventilated (HS/V) three phase motor. The 865D-2 can also be used as a Manual Adjust or Vdc/mA input three phase fan speed control. The 865D-2 is a direct replacement for the obsolete 865-3AA and 865D.
- Onboard diagnostics to verify proper installation
- LED indicators verify proper operation
- Multiple voltages 208-230/460 VAC
- NEMA-3R weatherproof
- 1/2 to 2 H.P. Motors, 8 amps max
- Monitor up to two liquid line temperature sensors (expandable up to 6 sensors with the addition of 851-MS Multiple Senor Selector)
- Monitor one Vdc or mA pressure transducer
- Can be used as a manual or Vdc/mA input three phase fan speed control
- Fully adjustable LOW and HIGH set points
- Detects three phase power faults
Why Measure Head Pressure using Temperature instead of Pressure?
Many people assume that the best way to control the head pressure from a compressor is to directly sense the line pressure using a sensor inserted into the liquid line.