Hitachi UTOPIA RAS-4HVRP2E - Defrost Operation RAS-3 HVRC2

5 Control System
Standard operation sequence RAS-3HVRC2 and RAS-(4-6)H(V)(R/N)(C/P)2E
SMGB0136 rev.0 - 07/2021
100
5.5.4 Defrost operation RAS-3HVRC2
Heating
Operation
(*) Refer to Service Manual for the timing diagram of the reversing valve.
Yes
No
No
Yes
Defrosting
Start Condition is
approved
Defrost Operation
Defrosting
Stop Condition is
approved
Thermo settings
Temperature +2°C or higher
IU Air
Outlet Temp.
< 77°F
(25°C)
≥ 86°F
(30°C)
MIF
Operation at Slo Fan
Speed
≥ 77°F (25°C) and
< 86°F (30°C)
MIF
Operation at Low Fan
Speed
MIF
Operation at
Set Fan Speed
Indoor fan in slow
wind speed
Four-way valve (21)
Energization OFF
(Y52H) Energize
(52H) Energize
Display during
defrosting
Auxiliary Electric heater (H)
operation
Indoor fan (MFE) Stop
Outdoor fan (MFC) Stop
No
Yes
Compressor
(MC) Stop
Compressor
(MC) Operation
Elapsed
time 30 s
Defrost Operation
Four-way
valve (21)
Energization ON
Display disappears
during defrosting
Indoor
suction, Air
temperature
Thermo settings
Less than preset
temperature
Compressor MC
Stop
(*)
I.U: Indoor Unit
: Actuator