Installation manual

38GL_M…G
R-410A
GB - 11
ENGLISH
Testing, Pump Down and check the refrigerant charge
Testing
IMPORTANT:
Test each single unit separately.
Pump Down
Pump down is an operation intended to collect all the system
refrigerant in the outdoor unit.
This operation must be carried out before disconnecting the
refrigerant tubing in order to avoid refrigerant loss to the
atmosphere, if it becomes necessary to disconnect the
refrigerant connections for unit repair, removal or disposal; in
this case, after removal, unit must be delivered to an
appropriate disposal centre or the original dealer.
Shut off the liquid valve with the Allen wrench.
Turn the system on in cooling with fan operating at high velocity.
(Compressor will immediately start, provided 3 minutes have
elapsed since the last stop).
After 2 minutes of operation, shut the suction valve with the same
wrench.
Turn the system off and switch mains supply off.
Disconnect tubing.
After disconnection, protect valves and tubing ends from dust.
Check the refrigerant charge
• This check becomes necessary after any refrigerant leak due to
incorrect connection, or after replacement of the compressor.
• The best method to correctly charge refrigerant is to
completely empty the refrigerant circuit using refrigerant
recovery equipment.
Then charge the exact quantity of refrigerant according to the
data shown on the unit nameplate. This can be done with
charging equipment of the “Dial a charge” type.
15
10
5
24
22
20
18
16
14
12
20 25 30 35 40
쐃
쐇
쐋
• R-410A refrigerant cylinders contain a dip tube which allows
liquid refrigerant to flow from the cylinder in an upright
position.
Charge R-410A units with cylinder in upright position and a
commercial-type metering device in manifold hose in order to
vaporize the liquid refrigerant before it enters in the unit.
Charge refrigerant into suction-line.
• The refrigerant charge check can be carried out using the
superheating method; this is only possible, if the ambient
temperature is above 15°C.
• Superheating method
IMPORTANT:
To check the refrigerant charge in the cooling only units it is
important that all the indoor units are operating
contemporaneously.
Check temperature at the points shown in the illustration:
- Te (evaporating temp.) with manometer
- Ta (suction gas temp.) contact thermometer superheat (Ta - Te)
should equal the table value ± 2°C.
If superheat is outside the indicated limits, proceed as follows:
• If superheat is lower than the table value, the refrigerant charge is
excessive or the air quantity passing through the evaporator
(indoor unit) coil is insufficient. If superheat is higher than the table
value, the refrigerant charge is insufficient or the expansion device
(capillary or Accurater) is clogged.
• By knowing the temperature of the air entering the condenser coil
it is possible to determine the correct value of the superheat, we
should have at the compressor inlet.
Wait approx. 5 minutes after adding or removing refrigerant; if the
room conditions or those of the air entering the condenser vary
during the charging operation, repeat all readings.
쐃 Superheat °C
쐇 Condenser entering dry bulb temperature °C
쐋 Evaporator entering wet bulb temperature °C