Defrost Operation - Hitachi FSXN Series Service Manual

5 Control system

5.2.8 Defrost operation

Heating
Heating Operation Time
40 Minutes or Above
No
Defrosting
Defrosting Time is
9 Minutes or Above
Yes
Defrosting
Completion
Heating
(1)
The defrost signal is transmitted to the indoor unit during the defrost operation. After the signal is received, the remote
control liquid crystal display indicates DEFROST and the indoor unit fan stops.
(2)
For heat recovery systems with 20 HP or more, the RVR1 reversing valve will not operate.
(3)
For heat recovery systems with 20 HP or more, switching power ON/OFF of the RVR2 reversing valve will be carried out
in each outdoor unit.
104
SMGB0065 rev. 1 - 12/2010
Yes
Compressor Operating
at Low Frequency
Fixed Opening
Degree of Electronic
Expansion Valve
PID Control for
Super Cooling Electronic
Expansion Valve
Evaporating Temperature
No
(Te) at Heat Exchanger is
15ºC or Above
Yes
Small
Temperature Difference
between Outdoor Temperature
and Evaporating Temperature (Te)
at Heat Exchanger
RVR1 : ON
RVR2 : OFF
Outdoor FAN MOF1 : OFF
1 Minute Later
High Frequency
No
Discharge Gas Pressure
is 1.7MPa or Above
RVR1 : OFF
RVR2 : ON
Big
Operation
No
Yes