Danfoss Optyma Trio HU2900D50 Application Manual Download Page 15

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Installation and Operation

4.7 Refrigerant and oil

charge

4.8 Verification before

operating

4.9 First start-up

4.10 Verification of the unit

while operating

• Use individual protection equipment (IPE)

such as safety glasses and gloves.

• Never start the compressor under vacuum.

Keep the compressor switched off.

• Before performing the refrigerant charge,

verify if the oil level is between ¼ and ¾ on the
compressor oil display. If necessary, add oil to
the compressors, refer to the compressor’s label
for oil type.

• Only use the coolant for which the unit was

designed for.

• Perform the refrigerant charge in liquid phase

into the condenser and in the liquid receiver.

Make sure to perform a slow refrigerant
charge until it reaches 4-5 bar in systems
with R404A/507.

• Never put liquid refrigerant through the

suction line.

• Never use additive or oil mixtures.
• The remaining charge is carried out until the

installation has reached a stable nominal
condition level during the operation.

• Never leave the filling cylinder connected to

the system.

• Use safety devices according to locally

applicable regulations and security standards.

• Verify if all electrical connections are attached

correctly and in accordance with the local
regulations.

• Keep the crankcase heater switched on for at

least 12 hours before the system start-up, for the
guarantee of proper lubrication and elimination
of the liquid refrigerant from the compressor's
crankcase.

• Never switch on the unit without having

performed a refrigerant charge .

• All service valves must be in the open position.

See figure 5.

• Verify if the power supply is adequately

connected.

•  Verify if the crankcase heater is working.
• Verify if the fan can rotate freely.
•  Verify if high and low pressure are balanced.
•  Energize the unit and verify the conformity of

the wiring, the tension in the terminals and the
phase sequence.

• The potential reverse rotation of a three-phased

compressor can be detected by no pressure
increase, an abnormal sound level of the
compressor and a lower energy consumption
than the one expected. In this case, immediately
switch off the unit and connect the phases to
their appropriate terminals.

• If the direction of rotation is correct, the indication

of low pressure on the low pressure gauge must
display a decreasing pressure and the indication
of high pressure in the high pressure measurer
must display an increasing pressure.

• The electronic buoys must comply with the

indication.

• Check the rotation direction of the fan. The air

must flow from the condenser to the fan (air
flow from bottom to top).

• Check the high pressure stabilization and the

power supply stability.

• Check the suction overheating to reduce the risk

of the return of liquid to the compressor.

• Observe the compressor oil level in the

beginning and during the operation to confirm
that the oil level remains visible.

• Verify all tubing with respect to unusual

vibration. The movements exceeding 1.5mm
require corrective measures, as the use of
fixation supports in the tubing.