26 Chapter 4 System Power-On Commissioning
Liebert CRV+ Series Air Conditioner User Manual
8. In low temperature environment, it may be necessary to manually raise the condensing pressure up to 21Bar by
manually shielding some condensing area and limiting condensing air volume
Electric part
1. Check that the voltage of the main power supply is within ±10% of the rating, and that the isolation switch of the
air-cooled condenser of the outdoor unit has been closed.
2. Check that all power and control circuits are properly connected. Fasten all connection connectors.
3. Check that the power cables and the low voltage control cables are laid away from each other.
4. Check that the water level switch cable has been connected and the water level floater can work normally.
4.2.2 Commissioning Procedures
1. Switch off the MCBs of various components. Switch on the main isolation switch and control board MCBs. Check
that the control voltage is 24Vac ± 10%.
2. Start the unit and measure the fan operating current of each phase.
3. Connect the high and low pressure composite pressure gauge to the needle valve on the ball valve of liquid pipe
and to the needle valve interface behind the electrical expansion valve. Pump the cooling system vacuum to -30in.Hg
(pumping time > three hours), and hold the state for four hours. The pressure should not rise, and the sight glass
appears green (to ensure the cooling system vacuum and dry effect, pump the cooling system repeatedly at least
three times). If liquid line solenoid valve is equipped in the system, you need to select pump vacuum mode in manual
mode, then open the liquid line solenoid valve and pump vacuum again.
4. After pumping system vacuum and checking, charge proper amount of liquid refrigerant quickly in the cooling
system (usually charge until the pressures inside the refrigerant container equalizes with that in the cooling system).
Connect the composite pressure gauge to the refrigerant cylinder. Note to exhaust the air inside the tube of the
gauge.
Static charging (charging before startup): connect the high and low pressure composite pressure gauge to the needle
valve on the ball valve of liquid pipe and to the needle valve interface behind the electrical expansion valve. Keep the
refrigerant cylinder upside down during static charging.
When the refrigerant is fully filled before the charging amount reaches the calculated charging value, you should stop
static charging.
Warning
It is strictly prohibited from charging refrigerant from the needle valve on the compressor suction pipe, otherwise, the compressor
damage caused by it will make the warranty invalid.
Note
1. The air inside the tube of the composite pressure gauge should be exhausted.
2. After static charging is completed, it is strictly prohibited from powering on the unit at once, to prevent the compressor from
starting and running with liquid.
The unit cannot be powered on at once after static charging: before power-on, ensure that the compressor crankshaft
box heating band has been preheated for above 12 hours. If the preheating time is not enough, you should use an
electrical blower or other safe heating source to heat the lower part of the compressor shell for 30min, to evaporate
the liquid refrigerant.
Dynamic charging: keep the refrigerant cylinder standing on its base and open the low pressure valve to add small
amount of air into the compressor suction hole, then start the compressor manually (compressor output 72%, fan
output 60%) and perform dynamic charging. After the compressor starts, if the refrigerant cannot be charging, you
can place the refrigerant cylinder upside down, and regulate the opening of the low pressure valve to make the low
pressure gauge pointer between 10bar and 11bar, to ensure that the charging refrigerant is gas.
When the compressor starts and operates, charge gas refrigerant (R410A) dynamically till there is no air bubble in
the sight glass, the condensing subcooling degree reaches above 3K, and the suction overheating degree reaches
above 7K.
To Next Page
Loading...
Need help?
General
