Operation Of Solenoid Valves - Sanyo ECO-i 3-WAY MULTI SYSTEM Service Manual

6. Operation of Solenoid Valves

6-1. Refrigerant Control Valve [RCV]
The main purpose of this valve is to detect the flow of refrigerant (refrigerant volume) on the indoor-unit side when
the outdoor unit heat exchanger is functioning as a condenser. When the valve determines that there are signs of a
low refrigerant level, refrigerant is supplied from the receiver tank to the system.
(1) The OFF conditions take priority over the ON conditions for this valve.
(2) This valve is OFF when the outdoor unit is stopped.
(3) This valve is ON when special control is in progress.
(4) Control during normal operation
(A) Cooling operation
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This valve turns ON when symptoms of insufficient refrigerant gas occur at an
indoor unit.
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This valve turns ON when the outdoor air temperature is 15°C or below. (Under
these conditions the high pressure is low and refrigerant flow becomes poor.)
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This valve turns OFF when symptoms of refrigerant overcharge are detected at
the outdoor unit.
(B) Mixed cooling/heating operation
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The RCV turns ON at stopped outdoor units when the heat exchanger at
another outdoor unit is functioning as a condenser.
6-2. Refrigerant Balance Valve [RBV] – Gas Purge Valve
The main purpose of this valve is to detect the flow of refrigerant (refrigerant volume) on the indoor-unit side when
the outdoor unit heat exchanger is functioning as an evaporator. When the valve determines that there are signs of
excess refrigerant, refrigerant is recovered at the receiver tank.
This valve is ON during heating operation and when the outdoor unit heat exchanger is functioning as an
evaporator during mixed heating/cooling operation. It also turns ON in order to recover refrigerant at the outdoor
unit after heating operation is stopped.
* This valve is never ON at the same time as the RCV.
(1) The OFF conditions take priority over the ON conditions for this valve.
(2) This valve turns ON for 30 – 50 seconds after the outdoor unit stops, and then turns OFF.
(3) This valve turns ON once after the outdoor unit starts.
(A) Heating operation
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This valve turns ON when poor refrigerant flow at an indoor unit is detected,
and when symptoms of overcharge are detected.
After the valve turns OFF, it will not turn ON again for 15 minutes.
(B) Mixed heating/cooling operation
●
This valve turns ON when poor refrigerant flow at an indoor unit is detected,
and when symptoms of overcharge are detected, if the heat exchanger at the
outdoor unit is functioning as an evaporator.
(4) This valve turns OFF when an abnormal drop in discharge gas temperature is detected.
(5) This valve turns OFF when a drop in the detected receiver tank temperature
continues for a set length of time, and when liquid back-flow is judged to be occurring.
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3-WAY ECO-i SYSTEM
Control Functions
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