Bard MULTI-TEC W18AAPA, Инструкция по эксплуатации

Страница: 98 / 116

Manual 2100-479
Page
5 of 11
R-410A System Charging
Even though R-410A has a very small fractionation potential,
it cannot be ignored completely when charging. To avoid
fractionation, charging of an air conditioner or heat pump
system incorporating R-410A
shall be done with “liquid”
to maintain optimum system performance. To insure that
the proper blend composition is charged into the system, it
is important that liquid only be removed from the charging
cylinder. Some cylinders supplied by manufacturers have
dip tubes, which allow liquid refrigerant to be removed from
the cylinder when it is in the upright position. Cylinders
without dip tubes have to be tipped upside down in order
for liquid to be removed. The Service Technician must
differentiate between which type of charging cylinder
they are using to avoid removing vapor refrigerant instead
of liquid refrigerant to avoid fractionation and for safety
concerns.
Connect the gauge manifold to the high and low side. Allow
liquid to enter the high side only. The high side will hold 80-
100% of the total charge. When liquid stops ���� close
high side port. The remainder of the charge will be added
to the low side. Keep in mind two issues: ��� never start
the compressor with less than 55 psig of suction pressure.
Secondly, make sure the liquid is throttled, thus vaporized
into the low side of the system to avoid compressor
damage. A throttling valve can be used to insure that liquid
is converted to vapor prior to entering the system. Proper
manipulation (restricting) of the manifold gauge set can also
act as a throttling device to insure liquid is not entering the
compressor.
CHARGING
1.
Single Package Units
— Refer to the unit serial plate for
the full operating charge.
PRELIMINARY CHARGING STEPS
If the system has been open to the atmosphere, the ���
dryer should be replaced and then evacuated. Then proceed
as follows:
1. Attach a drum of proper, clean refrigerant to the center
port of the charging manifold with one of the charging
hoses.
2. Attach a second charging hose to the suction gauge (low
pressure) side of the gauge manifold.
3. Remove the cap from the suction line valve.
4. Loosely attach the suction gauge hose to the line valve.
Open the valve on the refrigerant drum and the suction
valve on the charging manifold slightly to purge the air
from the manifold and hoses before tightening the ����
5. Attach the third hose to the high pressure side of the
manifold and the liquid line valve. Repeat steps 3 and 4
above.
CHARGING THE SYSTEM BY WEIGHT
1. Connect manifold as instructed.
2. Place refrigerant drum upright on scale and determine
exact weight of the refrigerant and cylinder.
3. With manifold suction valve closed and manifold
discharge valve open, open refrigerant cylinder liquid
valve and allow pressure in system to balance with
pressure of cylinder or 80% of charge is in the unit -
whichever comes ���
4. When there is approximately an 80% charge, front seat
(close) the discharge manifold valve and let the system
stabilize for about �� minutes.
5. Start compressor by setting thermostat.
6. Finish charging with liquid by cracking the suction valve.
Open the manifold low pressure valve to allow refrigerant
to �� into the system. Throttle the manifold valve to
keep pressure about 100 psig for R-410A.
7. When the correct weight of refrigerant has been added to
the unit, close refrigerant cylinder valve and allow unit
to run for 30 minutes. Refer to Start-Up Procedure and
Check List for further start-up details.
8. Front seat gauge manifold valves, disconnect charging
and gauge hoses and replace all valve caps.