Service manual

Overview of the heating mode functions ESIE03–01
2–46 Part 2 – Functional Description
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3.5 4-way Valve Control
Applicable units RYP71-125L
Purpose The purpose of the 4-way valve control is to control how the superheated refrigerant passes through
the 4-way valve. The 4-way valve control carries out the changeover switching of the 4-way valve. This
changeover switching is only carried out during operation, because pressure difference is required to
move the internal cylinder.
Method The table below describes the 4-way valve control operation.
Time chart The time chart below illustrates the 4-way valve control.
Used input The 4-way valve control uses the following inputs:
When... Then the 4-way valve connects the outlet of the compressor with...
Cooling Outdoor heat exchanger.
Heating Indoor heat exchanger.
In... The 4-way valve is...
Heating, except for defrosting ON
P Cooling
P Dry keep
P Defrosting
OFF
C
ompressor
4-way valve
Defrosting
Unit mode
ON
OFF
OFF
ON
OFF
ON
Heating
Cooling / dry keep
3 min
Input
Connection on
indoor PCB
Connection on
outdoor PCB
Indoor air temperature R1T (auto changeover) X19A —
Outdoor heat exchanger temperature R2T (defrost) — X5A