moisture from the atmosphere, it loses its effective-
ness.
Recover the holding charge in the evaporator coil and then re-
move the sealing caps or discs from both the liquid and suction
connections on the evaporator coil per the following procedure:
1. Make sure the refrigerant in the lines has been recovered,
then drill a small hole through both the liquid disc and the
suction disc. If the holding charge has already been lost,
the coil should be leak-tested and the necessary repairs
should be made.
2. Move the dry nitrogen supply from the access port on the
liquid line service valve of the condensing unit to the hole
through the suction disc on the evaporator coil.
3. Unbraze the coil's liquid line disc while maintaining a flow of
dry nitrogen across the connection and through the hole in
the liquid line disc.
NOTE: If the liquid line has a solenoid valve, the valve
should be opened manually to permit the nitrogen
to flow freely.
4. After the disc has been removed, burnish the external sur-
faces and clean the internal surfaces as outlined above.
5. Move the dry nitrogen supply back to the access port on the
liquid line service valve.
6. Braze the liquid line to the liquid connection on the evapora-
tor coil while maintaining a minimum flow of dry nitrogen
through the liquid line, the evaporator coil and the hole in
the suction disc.
7. Unbraze the disc on the suction connection of the evapora-
tor coil while maintaining the flow of dry nitrogen.
8. After the disc has been removed, burnish the external sur-
faces and clean the internal surfaces as outlined above.
The suction piping can now be brazed to the suction connec-
tion on the evaporator coil while maintaining a minimum flow of
dry nitrogen.
Before brazing the suction line to the condensing unit;
1. Move the dry nitrogen supply to the access port on the suc-
tion service valve of the condensing unit.
2. Burnish the external surfaces and clean the internal sur-
faces of both the suction connection and the suction piping.
The suction line can now be brazed to the suction connection
on the condensing unit while maintaining the flow of dry nitro-
gen.
After the liquid and suction lines have been installed, the sys-
tem should be evacuated and charged.
EXTENDING THE SERVICE PORTS
1. Loosen the screws securing the service ports in shipping
position. (See FIG 6).
2. Push the service ports through the corner post.
3. Tighten the screws to secure the service ports for installa-
tion.
EVACUATION AND CHARGING
Determine the required weight of refrigerant using Table 2,
Physical Data, and Table 6 Refrigerant Line Charge. Table 2
includes operating charge based on the unit plus 25 feet of re-
frigerant lines. Table 6 includes data required to adjust the
charge for line lengths other than 25 feet.
With the liquid and suction line service valves closed, connect
a vacuum pump through a charging manifold to the access
ports on both the liquid and suction line service valves.
NOTE: The vacuum pump connection should be short and no
smaller than 3/8" O.D.
The refrigerant lines and the evaporator coil can now be evacu-
ated to 500 Microns without disturbing the condenser coil or the
compressor.
After proper evacuation and dehydration, charge the required
weight of liquid refrigerant through the access port on the liquid
line service valve.
CAUTION: Do not charge liquid refrigerant through the com-
pressor suction connection.
CAUTION: Do not attempt to start the compressor without at
least 8 hours of crankcase heat or compressor
damage will occur.
If the required amount of refrigerant cannot be added in this
manner, open the liquid and the suction line service valves
fully. Turn the stem of the liquid service valve clockwise 1/4 turn
to open its access port for reading pressure.
Start the compressor (after 8 hours of crankcase heat) and
continue to charge refrigerant gas through the access port on
the suction service valve.
Open the liquid service valve fully to close its access port after
the system is charged.
CAUTION: Never operate the compressor while under a deep
vacuum.
CAUTION: Do not attempt to start the compressor without at
least 8 hours of crankcase heat or compressor
damage will occur.
After proper evacuation and dehydrating of the unit, charge the
unit as described above until the moisture indicating sight glass
is clear. Add approximately 1 extra pound of refrigerant for the
HCE090 and 120 or 3 pounds for the HCE150 to assure a liq-
uid refrigerant seal at the expansion valve under all operating
conditions. If necessary, block the flow of condenser air to as-
sure a head pressure of 280 psig during the charging opera-
tion.EVACUATION AND CHARGING
035-15406-002-A-0504
10
Unitary Products Group
DO NOT ATTEMPT TO START THE COMPRESSOR WITH-
OUT AT LEAST 8 HOURS OF CRANKCASE HEAT OR COM-
PRESSOR DAMAGE WILL OCCUR.
