Hitachi RAS-(4-12)HNP(1)(E) - Prevention Control for High Pressure Increase During Cooling Operation

5 Control System
156
SMGB0087 rev.0 - 12/2013
5.5.2 Prevention control for high pressure increase during cooling operation
This function is performed to prevent the abnormal condition (Alarm Code: 02) when the air ow volume is decreased
by a seasonal wind against air outlet of the outdoor unit. When the following conditions are met, the forced Thermo-OFF
operation will be performed.
The cause of stoppage will be “13” during Thermo-OFF.
RAS-(2-2.5)HVNP1 / RAS-3HVNC1
1 Y52C is turned “ON” during the cooling operation, or RY1 is turned “ON” (during the compressor operation).
2 Pressure switch for control is turned “ON”.
ON 3.6MPa
OFF 2.85MPa
3 Outdoor liquid pipe temperature ≥ 55ºC
RAS-(4-10)H(V)NC1(E)
1 Y52C is turned “ON” during the cooling operation, or RY1 is turned “ON” (during the compressor operation).
2 Pressure switch for control is turned “ON”.
ON 3.6MPa
OFF 2.85MPa
3 Condensation temperature ≥ 62ºC
RAS-(3-12)H(V)N(P/C)(1)(E)
1 Y52C is turned “ON” during the cooling operation, or RY1 is turned “ON” (during the compressor operation).
2 High Pressure ≥ 3.8MPa.