Service manual

ESIE04-01 General Functionality
Part 2 – Functional Description 2–15
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1.11 4-way Valve Control
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 a certain 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.
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
Compressor
4-way valve
Defrosting
Unit mode
ON
OFF
OFF
ON
OFF
ON
Heating
Cooling/Dry
RZQ - Final.book Page 15 Monday, September 20, 2004 11:24 AM