Daikin VRV Service Manual

Si30-408 Other Functional Operations
Basic Information 35
5. Other Functional Operations
5.1 Explanations on Main Functional Control
5.1.1 Cooling Operation
5.1.2 Heating Operation
Compressor capacity control
Constant evaporation temperature (Te) control
(Basic target value: R22 = 5.5°C, R407C = 7.5°C, R410A = 6°C *Compensation is
applied)
Indoor electronic expansion valve
control
Constant superheated degree (SH = Tg – Tl) control
(Basically compensation of 5°C is required. As to R407C unit, temperature gradient
compensation is applied.)
High pressure stepping down
control
As rising of the high pressure, decreased the compressor capacity.
High pressure protection control Forcedly thermostat-off with limitation on retrying
Low pressure stepping down
control
Low pressure stepping down control is not made.
(Capacity is decreased by normal control of compressor.)
Low pressure protection control Hot gas bypass is on.
→ Forcedly thermostat-off with limitation on retrying
Low outdoor temperature cooling
control
As lowering of the high pressure, outdoor fan is controlled. (fan-tap drops).
Cooling overload control
Instruction of forcedly opening degree is given to indoor electronic expansion valve.
(Disregard of superheated degree control, even opening degree)
Discharge pipe temperature control
Based on discharging pipe temperature Td and discharging superheated degree
DSH = Td – Tc,
Injection is on.
→ Compressor capacity is lowered.→ Forcedly thermostat off with
limitation on retrying
Oil return control
Based on cumulative operation time, oil return operation should be carried out
periodically.
(According to the state of operation, cumulative operation time may be compensated.)
Compressor capacity control
Constant condensing temperature (Tc) control
(Basic target value: R22 = 46°C, R407C = 48°C, R410A = 46°C *Compensation is
applied)
Outdoor motorized valve control
Constant superheated degree (SH = Ts – Te) control
(Basic 5 deg. compensation is applied.)
Indoor motorized valve control
Constant subcooled degree (SC = Tc – Tl) control
(Basic compensation of 5 deg is applied.)
High pressure stepping down
control
(= Heating overload control) Compressor capacity control
→ Outdoor electronic
expansion valve control (Disregard of superheated degree control) and Outdoor fan
control (Fan tap is lowered.)
High pressure protection control Forcedly thermostat-off with limitation on retrying
Low pressure stepping down
control
As lowering of the low pressure decreases the compressor capacity.
Low pressure protection control Hot gas bypass is on.
→ Forcedly thermostat-off with limitation on retrying
Defrost control Based on lowered Tb, defrosting operation is carried out. (Compensation based on Ta).
Discharge pipe temperature control
Based on discharging pipe temperature Td and discharging superheated degree
DSH = Td – Tc,
Injection is on. → Compressor capacity is lowered → Forcedly thermostat-off with
limitation on retrying
Oil return control
Based on cumulative operation time, oil return operation should be carried out
periodically.
(According to the state of operation, cumulative operation time may be compensated.)

Daikin VRV Specifications

General

Brand	Daikin
Energy Efficiency	High
Control	Centralized and individual zone control
Inverter Technology	Yes
Type	Variable Refrigerant Volume (VRV)
Cooling Capacity	Varies by model
Heating Capacity	Varies by model
Refrigerant	R-32 or R-410A
Application	Commercial buildings, large residential spaces
SEER	Varies by model
HSPF	Varies by model
EER	Varies by model
COP	Varies by model
Sound Level	Varies by model
Indoor Unit Options	wall-mounted, ducted