Sinclair SCV-750EB Service Manual page 21

Key components:
1. Compressor
Maintains pressure differential between high and low pressure sides of the refrigerant system.
2. Fan:
Ventilates the air side heat exchanger.
3. Air side heat exchanger:
In the cooling mode, the heat of the refrigerant from the water side heat exchanger can be released into the air.
In the heating mode, the refrigerant can absorb the heat in the air and provide it to the water side heat exchanger.
4. Water side heat exchanger:
In cooling mode, the refrigerant can absorb heat from the water and reduce the temperature of the water.
In heating mode, the refrigerant can release heat into the water and increase the temperature of the water.
5. Four-way valve:
Controls refrigerant flow direction. Closed in cooling mode and open in heating mode. When closed, the air side heat
exchanger functions as a condenser and water side heat exchanger functions as an evaporator; when open, the air side heat
exchanger functions as an evaporator and water side heat exchanger function as a condenser.
6. Vapor-liquid separator:
Stores liquid refrigerant to protect the compressor from liquid hammering.
7. Oil separator:
Separates oil from gas refrigerant pumped out of the compressor and quickly returns it to the compressor. Separation
efficiency is up to 99%.
8. Plate heat exchanger (Economizer):
In cooling mode, it can improve super-cooling degree and the super-cooled refrigerant can achieve better heat exchange in
indoor side. In heating mode, the refrigerant comes from the plate heat exchanger going to the compressor can enhance the
refrigerant enthalpy and improve the heating capacity in low ambient temperature. Refrigerant volume in plate heat
exchanger is controlled according to temperature different between plate heat exchanger inlet and outlet.
9. Electronic expansion valve:
Controls refrigerant flow and reduces refrigerant pressure.
10. Solenoid valve SV5 (defrost):
Multiple functions for enhancing reliability.
11. Solenoid valve SV6 (by pass):
Increase refrigerant flow.
12. Solenoid valve SV8A, SV8B (injection):
Enhance enthalpy and capacity.
13. High and low pressure switches:
Regulate refrigerant system pressure. When the refrigerant system pressure rises above the upper limit or falls below the
lower limit, the high or low pressure switches turn off, stopping the compressor.
14. Discharge temperature switch:
Protects the compressor from abnormally high temperatures and transient spikes in temperature.
15. High pressure sensor:
Measures compressor discharge side pressure of refrigerant.
16. Low pressure sensor:
Measures compressor suction side pressure of refrigerant.
17. Air purge valve:
Automatically removes air from the water circuit.
18. Safety valve (water side):
Prevents excessive water pressure by opening at 6bar and discharging water from the water circuit.
19. Water flow switch:
Detects water flow rate to protect the compressor and water pump in the event of insufficient water flow.
20. Safety valve (refrigerant side):
Prevents excessive refrigerant pressure by opening at 42bar and discharging refrigerant from the refrigerant system.
21. Crankcase heater:
Prevents refrigerant from mixing with compressor oil when the compressors are stopped.
22. Water side heat exchanger electric heater:
Protects the water side heat exchanger from ice formation.
23. Water flow switch electric heater:
Protects the water from ice formation.
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