Daikin FTX09NMVJU, Service Manual

Page: 54 / 145

Control Specification SiUS091601E
43 Functions and Control
3.3 Controls at Mode Changing / Start-up
3.3.1 Preheating Control
Outline The inverter operation in open phase starts with the conditions of the outdoor temperature, the
discharge pipe temperature, the radiation fin temperature and the preheating command from the
indoor unit.
Detail Outdoor temperature
≥
–2.5°C (27.5°F)
→
Control A (preheating for normal state)
Outdoor temperature < –2.5°C (27.5°F)
→
Control B (preheating of increased capacity)
Control A
Š
ON condition
Discharge pipe temperature < 0°C (32.0°F)
Radiation fin temperature < 85°C (185°F)
Š
OFF condition
Discharge pipe temperature > 2°C (35.6°F)
Radiation fin temperature
≥
90°C (194°F)
Control B
Š
ON condition
Discharge pipe temperature < 10°C (50.0°F)
Radiation fin temperature < 85°C (185°F)
Š
OFF condition
Discharge pipe temperature > 12°C (53.6°F)
Radiation fin temperature
≥
90°C (194°F)
3.3.2 Four Way Valve Switching
Outline The four way valve coil is energized / not energized depending on the operation mode. (Heating:
ON, Cooling / Dry / Defrost: OFF)
In order to eliminate the switching sound as the four way valve coil switches from ON to OFF when
the heating is stopped, the OFF delay switch of the four way valve is carried out.
Detail OFF delay switch of four way valve
The four way valve coil is energized for 160 seconds after the operation is stopped.