8
Refrigerant piping diagram
Single circuit only for 38AJ/AZ 008-036 units
Soldered plug with
pressure equalisation
port. To be removed
during installation.
General recommendations for field installation
Thermostatic expansion valve (TXV) and solenoid valve
•
The thermal expansion valve sensing bulb must be
installed after at least two 90
°
bends at the evaporator
outlet.
•
Ideally the TXV should be installed in a vertical pipe run.
If that is not possible, the valve may be rotated through a
full 90
°
, with the horizontal pipe remaining at the base.
•
The TXV and solenoid valves are installed as shown in
Figs. 1 to 5 (pages 9 and 10).
-
Liquid line solenoid valves are not necessary, if
single-circuit evaporators are used and the evaporator
has sufficient capacity to hold the whole refrigerant
charge. In this case the unit wiring must be modified;
please refer to Carrier Service Bulletin No. SB 005-
76-96 E.
-
Solenoid valves are needed with dual-circuit
evaporators to deactivate the upper section of the
evaporator coil and reduce the load on the
compressor (capacity unloaders operated by suction
pressure).
Legend:
1
Condenser
2
Liquid line valve
3
Filter drier
4
Sight glass
5
Fan cycling pressure switch
6
Suction valve
NOTE: The typical refrigeration circuit diagram shown does
not apply to all control types used.
7
Compressor
8
Discharge valve
9
Muffler
A
Circuit 1
B
Circuit 2
C
Option No. 97
Installation of piping
IMPORTANT:
•
In order to prevent vibration and possible pipe breaks
install proper pipe supports for all pipes at the point
where they leave the unit.
•
On all units, relieve the pressure of the holding charge
before opening the circuit.
•
Open all service valves:
-
on models 014 to 074, open the compressor suction
and discharge valves
-
on all models, open the liquid line shut-off valves.
•
Remove the protective cap from the Schrader port in the
liquid line valve and press on the valve depressor to
release the holding charge (nitrogen).
•
Unsolder the plugs and prepare the pipes for connection.
•
Install the filter-drier and moisture indicator (for 38AZ
units these must be specific for R-407C), as shown in
Figs. 1 to 5. Select the filter-drier for maximum unit
capacity and minimum pressure drop. Install the filter-
drier in the liquid line before the expansion valve and the
moisture indicator just after the shut-off valve in the same
line. These are available as factory-fitted option 97.
