Hitachi RAS-3HVRNS - Page 158

Preheating control of compressor
Operation
Temp. on the
top of comp.
CH : ON
> 55ºC
< 60ºC
≥ 60ºC
≤ 55ºC
CH : OFF
Temp. on the
top of comp.
Prevention control for high pressure increase
This function is performed to prevent the abnormal condition (Alarm: 02) when the outdoor air flow is decreased by a
seasonal wind against air outlet.
When the CMC is ON during cooling operation, PSC is ON and Tc is higher than Tc1+4 °C, forced thermo-off operation will
be performed.
Tc: Outdoor piping temperature.
Tc1: Outdoor piping temperature when PSC is ON.
PSC ON: 3.60 MPa.
However, if it occurs more than 6 times during operation, forced thermo-off operation will not be performed. Cause of
stoppage will be 13.
5 Control System
150
SMGB0060 rev. 1- 12/2010