5.1.3 Heat exchanger mode control
•
Heat recovery system: in accordance with the connected load of indoor units, the outdoor unit heat exchanger can
switch as indicated in the following table.
•
Heat pump system: in accordance with the operation mode of the indoor units, the outdoor unit heat exchanger can
switch as indicated in the following table.
N O T E
Outdoor unit heat exchanger mode at cooling: condenser (COND).
Outdoor unit heat exchanger mode at heating: evaporator (EVAP).
1 Heat exchanger mode:
•
COND: operating as condenser.
•
cond: avoid using the heat exchanger (under high pressure conditions).
•
EVAP: operating as evaporator.
•
evap: avoid using the heat exchanger (under low pressure conditions).
2 Expansion valve control method:
•
Pd: normally, completely open (the opening depends on the refrigerant cycle conditions). PI control is
carried out to reach the discharge pressure objective value when it decreases.
•
TdSH: PI control is carried out to reach the compressor TdSH objective value.
•
Heat exchanger SH: PI control is carried out to reach the heat exchanger SH objective value.
The number of outdoor unit: 1
Heat exchanger mode
Cooling mode
Mainly cooling mode
Mainly heating mode
Heating mode
Defrost mode
COND
D1
D1-1
D4
EVAP
DEF1
Heat exchanger condition
COND
COND
cond
EVAP
EVAP
COND
Reversing valve
RVR2
OFF
OFF
OFF
ON
ON
OFF
RVR1
ON
OFF
OFF
OFF
OFF
ON
Expansion valve
MV1
Pd
Pd
Heat exchanger SH
Completely open
MVB
TdSH
TdSH
Ps protection
TdSH
The number of outdoor unit: 2
Heat exchanger mode
Cooling mode
Mainly cooling mode
Mainly heating mode
Heating mode
Defrost mode
COND
D1
D2
D3
D4
EVAP
DEF2
DEF1
With CH unit
Without CH unit
Main outdoor
unit
Heat exchanger condition
COND
COND
COND
cond
EVAP
EVAP
COND/EVAP
COND
Reversing valve
RVR2
OFF
OFF
OFF
OFF
ON
ON
ON/OFF
OFF
RVR1
ON
OFF
OFF
OFF
OFF
OFF
OFF
ON
Expansion valve
MV1
Pd
Pd
Heat exchanger SH
Completely
open/Heat
exchanger SH
Completely
closed
MVB
TdSH
TdSH
Secondary
outdoor unit
Heat exchanger condition
COND
COND
evap
EVAP
EVAP
EVAP
COND/EVAP
COND
Reversing valve
RVR2
OFF
OFF
ON
ON
ON
ON
ON/OFF
OFF
RVR1
ON
OFF
OFF
OFF
OFF
OFF
OFF
ON
Expansion valve
MV1
Pd
Pd
Completely closed
Completely
open/Heat
exchanger SH
Completely
closed
MVB
TdSH
TdSH
5 Control system
94
SMGB0065 rev. 1 - 12/2010