Specifications

Control Specification SiBE04-624
64 Function and Control
3.3 Four-way Valve Operation
Outline Because the four-way valve only operates properly when there is an adequate pressure
difference, the four-way valve compensation function has been implemented to insure this
minimal pressure difference.
Detail The four-way valve compensation function insures a good four-way valve operation by
demanding a certain minimal operation frequency for a certain time. By doing this, the unit is
ensuring the switching of the four-way valve.
When this function is enabled, the unit will not look at the other safeties (with the exception of
input current control).
The four-way valve function compensation is engaged in four cases
z
When starting the compressor for heating.
z
When the operation mode is changed.
z
When starting the compressor for defrosting.
z
When starting the compressor after a power failure (auto-restart).
No power to the valve --> cooling.
Power to the valve --> heating.
Frequency [Hz] Time [sec]
Cooling 52
60
Heating
outdoor temperature < 16°C 52
outdoor temperature ≥ 16°C - 0.9 x outdoor temperature + 68