Electronic Expansion Valve Control - Daikin FTXS20K2V1B Service Manual

SiBE041134

3.11 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
Open Control
1. Electronic expansion valve control when starting operation
2. Electronic expansion valve control when the frequency changes
3. Electronic expansion valve control for defrosting
4. Electronic expansion valve control when the discharge pipe temperature is abnormally high
5. Electronic expansion valve control when the discharge pipe thermistor is disconnected
Feedback Control
1. Target discharge pipe temperature control
Detail The followings are the examples of electronic expansion valve control which function in each
operation mode.
Function and Control
h
: Holding Functions
— : No Functions
Cooling
Starting control
Control when the frequency changes
Target discharge pipe temperature control
Control for disconnection of the discharge
pipe thermistor
High discharge pipe temperature control
Pressure equalizing control
Opening limit control
Heating
Starting control
Control when the frequency changes
Target discharge pipe temperature control
Control for disconnection of the discharge
pipe thermistor
High discharge pipe temperature control
Defrost control
Pressure equalizing control
Opening limit control
− h − − −
− − h − h
− − − −
h
− − − − −
−
h h h h
h − − − −
− h h h h
− − − −
h
− − −
h h
− − − h −
− − − − −
−
h h h h
− − − − −
h − − − −
− h h h h
Control Specification
− − −
− − −
− − −
−
h h
− − −
− − −
h h −
− − −
− − −
− − −
h h −
− − −
− −
h
− − −
h h −
33