Low Hz High Pressure Limit; Outdoor Electronic Expansion Valve Control - Daikin 3MKS50E3V1B Service Manual

SiBE121135

4.11 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. Zones are divided into three,
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.

4.12 Outdoor Electronic Expansion Valve Control

Outline
The following items are included in the outdoor electronic expansion valve control.
Outdoor electronic expansion valve is fully closed
1. Outdoor 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-
4. Liquid pipe temperature control for stopped rooms
5. Dew prevention control for indoor rotor
Open Control
1. Outdoor electronic expansion valve control when starting operation
2. Outdoor electronic expansion valve control when the frequency changes
3. Outdoor electronic expansion valve control for defrosting
4. Outdoor electronic expansion valve control for oil recovery
5. Outdoor electronic expansion valve control when a discharge pipe temperature is
6. Outdoor electronic expansion valve control when the discharge pipe thermistor is
7. Outdoor electronic expansion valve control for indoor unit freeze-up protection
Feedback Control
1. Target discharge pipe temperature control
Function and Control
A
Highest indoor
heat exchanger
temperature
among
operating rooms
A (°C)
B (°C)
C (°C)
conditioned)
abnormally high
disconnected
Dropping zone
Reset zone
Keep
zone
40/50/52/58/68/75 class
60
59
56
Control Specification
B
C
(R14587)
80/90 class
57
56
53
117