Wellea Monobloc
11
P
art
2
- Componen
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R
efrig
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Cir
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s
Key components:
1.
Accumulator:
Stores liquid refrigerant and oil to protect compressor from liquid hammering.
2.
Electronic expansion valve (EXV):
Controls refrigerant flow and reduces refrigerant pressure.
3.
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.
4.
High and low pressure switches:
Regulate refrigerant system pressure. When 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.
5.
Air purge valve:
Automatically removes air from the water circuit.
6.
Safety valve:
Prevents excessive water pressure by opening at 43.5 psi (3 bar) and discharging water from the water circuit.
7.
Expansion vessel:
Balances water system pressure. (Expansion vessel volume: 2L in 5/7/9kW units and 3.2L in 12-16kW units.)
8.
Water flow switch:
Detects water flow rate to protect compressor and water pump in the event of insufficient water flow.
9.
Backup heater:
Provides additional heating capacity when the heating capacity of the heat pump is insufficient due to very low
outdoor temperature. Also protects the external water piping from freezing.
10.
Manometer:
Provides water circuit pressure readout.
11.
Water pump:
Circulates water in the water circuit.
