Low Hz High Pressure Limit; Electronic Expansion Valve Control - Daikin SUPER MULTI NX G Series Service Manual

Control Specification

3.11 Low Hz High Pressure Limit

Outline
The upper limit of high pressure in a low Hz zone is set. The upper limit of the indoor heat
exchanger temperature is also set by the operating frequency. There are 3 zones. Reset zone,
keep zone, and dropping zone, and the frequency control is carried out according to each zone.
Detail
Note: Dropping: The system stops 2 minutes after staying in the dropping zone.

3.12 Electronic Expansion Valve Control

Outline The following items are included in the electronic expansion valve control.
Electronic expansion valve is fully closed
1. Electronic expansion valve is fully closed when turning on the power.
2. Pressure equalizing control
Room Distribution Control
1. Gas pipe isothermal control
2. SC (subcooling) control
3. Liquid pipe temperature control (with all ports connected and all rooms being air-conditioned)
4. Liquid pipe temperature control for stopped rooms
5. Condensation prevention control for indoor motor
Open Control
1. Electronic expansion valve control when starting operation
2. Electronic expansion valve control when frequency is changed
3. Electronic expansion valve control for defrosting
4. Electronic expansion valve control for oil recovery
5. Electronic expansion valve control when a discharge pipe temperature is abnormally high
6. Electronic expansion valve control when the discharge pipe thermistor is disconnected
7. Electronic expansion valve control for indoor unit freeze-up protection
Feedback Control
1. Discharge pipe temperature control
53
Highest indoor
heat exchanger
temperature
among the
operating room
18 class 24/32 class
60°C (140°F) 57°C (135°F)
59°C (138°F) 56°C (133°F)
56°C (133°F) 53°C (127°F)
Dropping zone
(R12297)
Function and Control
SiUS12-928_A