Refrigeration Maintenance and Service Operations
148
Installation
1. Clean the tubes for soldering.
2. Place the heat exchanger assembly in the unit
and install the mounting hardware.
3. Solder the suction line connections.
NOTE: It is strongly recommended that dry
nitrogen be used to purge the system during
any solder operations (see “Using
Pressurized Nitrogen” in this chapter).
4. Solder the liquid line connections.
5. Pressurize the low side and check for leaks
(see “Refrigerant Leak Test Procedure” in this
chapter).
6. If no leaks are found, recover the leak test gas
(see “Refrigerant Recovery” in this chapter).
7. Evacuate the low side (see “Evacuation and
Cleanup of the Refrigeration System” in this
chapter).
8. Clean suction line to a bright polished
condition. Install feeler bulb in the feeler bulb
clamps on the suction line. Locate bulb on the
suction line in former position. The feeler bulb
must make good contact with the suction line
or operation will be faulty. Cover with
insulating tape.
9. Recharge the unit with R-404A (see
“Charging the System with Refrigerant” in
this chapter).
10. Perform a controller pre-trip test to verify
system operation and correct feeler bulb
installation.
Receiver Tank Replacement
Removal
1. Recover the refrigerant charge from the unit
(see “Refrigerant Recovery” in this chapter).
2. Unsolder the liquid inlet, liquid outlet and
warm gas bypass valve line connections.
3. Loosen the mounting nuts and remove the
tankate bulb on the suction
Installation
1. Install a new tank in the unit and tighten the
mounting bolts.
2. Solder the inlet line outlet line and warm gas
bypass line connections.
NOTE: It is strongly recommended that dry
nitrogen be used to purge the system during
any solder operations (see “Using
Pressurized Nitrogen” in this chapter).
3. Pressurize the refrigeration system and check
for leaks (see “Refrigerant Leak Test
Procedure” in this chapter).
4. If no leaks are found, recover the refrigerant
used for the leak test (see “Refrigerant
Recovery” in this chapter).
5. Evacuate the system (see “Evacuation and
Cleanup of the Refrigeration System” in this
chapter).
6. Recharge the unit with R-404A (see
“Charging the System with Refrigerant” in
this chapter).
7. Perform a controller pre-trip test to verify
system operation.
Low or High Pressure Cutout
Switch Replacement
Removal
1. Recover the refrigerant charge from the unit
(see “Refrigerant Recovery” in this chapter).
2. Turn the U
NIT ON/OFF switch OFF.
Disconnect electrical connections to the
switch.
3. Unsolder the switch:
• High pressure cutout switch: Unsolder
from the liquid line.
• Low pressure cutout switch: Unsolder
from the suction line.
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