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4.1 Leak tightness of the circuit
All connections must be systematically checked for leaks with an electronic leakage detector.
4.2 Evacuation
Evacuate the installation to about 200 micrometer Hg, to ensure a good quality vacuum.
It is recommended to evacuate simultaneously on both sides (HP and LP) to accelerate the
operation and to obtain an identical vacuum in the entire circuit.
4.3 Refrigerant charge
Charge the installation only with the refrigerant the unit has been designed for (refer to name
plate).
Where the refrigerant is a blend, charging must always be in the liquid phase, to avoid changes
of the composition.
Never start the compressor under vacuum (HP and LP), but slowly charge the refrigeration
circuit to 4 to 5 bar in the case of R404A and about 2 bar in the case of R134a.
The remaining charge is filled until the nominal operation conditions of the installation are
reached, when the unit is running. Please refer as well to the chapter “Verification before
start” before power is applied to the installation.
VERIFICATION BEFORE START
1. Compatibility of the power supply voltage with the one of the unit.
2. Calibration of the electrical protection devices.
3. Full opening of the service valves.
4. Working of the crankcase heater or the heating band.
5. Free rotation of the condenser’s fan.
6. Check the installation for possible faults.
VERIFICATION AFTER START
After some hours of operation, verify the following:
1. Voltage and power requirement of the unit.
2. HP and LP of the installation.
3. Rotation of the condenser’s fan.
4. Superheat.
5. Leak check.
Verify the smooth running of the installation.
Carry out a general inspection of the installation (cleanliness, unusual noises…)
4.4 Fan speed control
The rotation speed of the fan is controlled by a pressure device. Its role is:
- To avoid excessive condensation pressure in winter, which could interfere with the operation
of the expansion valve.
- To further reduce the sound level when the ambient temperature permits it.
Refer to annexe 6 for the possibilities of control.
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