INSTALLATION
The hot gas bypass should be installed per the following
procedure:
1. Open the access ports on both the liquid and suction stop
valves of the CA unit to release the refrigerant (if any) in the
system.
NOTE: If the hot gas bypass is installed when the liquid
and suction lines are being installed, the refrigerant
charge should have already been released.
2. Cut off the pinched end of the 7/8" spud connection on the
compressor discharge header of the condenser coil with a
tube cutter.
3. Secure the support bracket for the hot gas valve to the base
of the compressor compartment where it will not interfere
with compressor accessibility. The drawings in Figure 3 can
be used to fabricate a suitable support bracket in the field.
4. Secure the hot gas bypass valve to the "U"-shaped support
bracket as shown in Figure 1.
CAUTION: Never install a hot gas valve without a support
bracket. The weight of the valve could distort
the piping and refrigerant leaks could develop.
5. Connect a supply of dry nitrogen to the access port on the
liquid line stop valve.
6. Braze the line between the 7/8" OD spud connection on the
condenser coil header and the inlet to the hot gas valve and
the line between the outlet of the hot gas valve and the tee
connection between the expansion valve and the distributor
of the system’s first stage of capacity.
NOTE: The liquid line solenoid valves at the evaporator coil
should be closed and the hot gas bypass valve
should be open to assure an adequate flow of dry
nitrogen through the hot gas line while the connec-
tions are being brazed.
A hole must be made in the side panel of the
compressor compartment to route the hot gas
bypass line outside the CA unit.
7. Connect a 1/4" flare line between the access port on the
hot gas valve and the suction access port labeled either A
or B on Figure 2 on the compressor.
8. Connect the solenoid of the hot gas valve between termi-
nals C1 and T on the 24-volt terminal block of the CA unit.
The solenoid will close the hot gas valve when the cooling
requirement is satisfied, and the system will be able to shut
down after the normal pumpdown cycle.
NOTE: For a CA480 equipped with the multi-zone acces-
sory, the hot gas solenoid should be connected
between terminal M1 on suction pressure control
3SP and terminal T on block 6TB. For a CA600
equipped with the multi-zone accessory, the hot
gas solenoid should be connected between termi-
nal M1 on suction pressure control 4SP and termi-
nal T on block 6TB.
CAUTION: Always disconnect power to the unit when mak-
ing any electrical connections.
9. Insulate the entire hot gas bypass line.
After the system is charged, adjust the set point of the hot gas
valve per the manufacturer’s recommendation.
Unitary Products Group
5005 York Drive, Norman, Oklahoma 73069
Subject to change without notice. Printed in U.S.A
Copyright
by York International Corporation 1999. All Rights Reserved.
SHU 1M 597 .11
Code: SBY
550.13-N6Y(399)
FIG. 2- SUCTION ACCESS PORTS
FIG. 3- MOUNTING BRACKET - DIMENSIONS
