9
•
The second moisture indicator must be installed close to
the condenser to provide a means of checking the
refrigerant charge.
•
Complete the liquid line valve connections between the
moisture indicator and the evaporator.
•
Complete the low-pressure suction line connections
between the compressor and the evaporator. Do this with
nitrogen or another inert gas flowing through the
pipework to prevent oxidation of the copper.
Oil return
Condensing units with multiple-step unloading may require
double suction risers to ensure proper oil return at minimum load.
A reduction of the evaporator coil surface should be considered
as a means of achieving a refrigerant velocity that will ensure
that enough oil returns to the compressor. Liquid line solenoid
valves may be used in certain situations to accomplish this.
Bypass hot gas, if used, should be introduced before the
evaporator. Consult your local Carrier distributor.
The oil charge must be adjusted to allow for extra line length.
This is done by adding 1% of the nominal oil charge for the
compressor every 3 m of piping in excess of 16 m.
Insulation
The refrigerant suction line should be insulated in accordance
with the guidelines set forth in the Carrier System Design
Manual (3rd part).
Fig. 3 - 38AJ/AZ 046-074, single evaporator
Fig. 1 - 38AJ/AZ 008-036, single evaporator
Fig. 2 - 38AJ/AZ 014-036, dual evaporator
Legend:
1
38AJ/AZ liquid line
2
Filter drier
3
Solenoid valve
4
Evaporator
5
Thermostatic expansion valve TXV
6
Moisture sight glass
Legend:
1
Solenoid valves
2
Thermostatic expansion valve TXV
3
Evaporator
4
Moisture sight glass
5
Filter drier
6
Liquid line
Legend:
1
38AJ/AZ liquid line
2
Filter drier
3
Solenoid valve
4
Evaporator
5
Thermostatic expansion valve TXV
6
Moisture sight glass
A
Circuit 1
B
Circuit 2
