38GLS…G / 38YL-…G Puron
GB - 10
Pump Down and check the refrigerant charge
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.
Connect a gauge on low side during a condenser pump-down.
Compressor damage may occur if run at a negative suction
pressure.
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
➀
➂
➁
20
25
30
35
40
햲
Superheat
°
C
햳
Condenser entering dry bulb temperature
°
C
햴
Evaporator entering wet bulb temperature
°
C
• 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 above method must be used for heat pump systems
operating in heating, as operating difficulty in the winter season
(iced outdoor coil) impedes stable operating conditions. Hence the
refrigerant charge must be checked. In cooling only systems, or
heat pumps operating in the cooling mode, 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
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
±
2ºC.
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 metering device
(expansion valve or capillary) 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.
