Service manual

5-11
Sealed System
7. Cut filter-drier from condensing unit.
8. Remove sealant from cabinet where suction line
enters.
9. Remove evaporator and suction line as one piece.
10. Install new evaporator with attached suction line.
11. Seal cabinet.
12. Install new filter drier at condenser outlet.
13. Evacuate and charge system using the
recommended procedure described under
Evacuating and Recharging.
Installing Evacuation and
Recharging Equipment
1. Disconnect refrigerator/freezer from electrical supply.
2. If compressor was replaced, install correct sized
process tube adapter on process tube.
If compressor was not replaced, cut process tube
with tubing cutter leaving as much tube as possible
and install correct size process tube adapter.
3. Install correct sized process tube adapter on
high-side process tube.
4. Attach refrigeration service gauge manifold to
system in following order: (See Figure 5-4)
• Low-side (compound gauge) hose to suction
side process tube adapter.
• High-side (pressure gauge) hose to high-side
process tube adapter.
• Center port manifold hose before hand shut-off
valve to charging cylinder.
• Center port manifold hose after hand shut-off
valve to vacuum pump.
DO NOT unbraze old filter-drier from system. This
will vaporize and drive moisture from desiccant
back into system. The old filter-drier should be cut
out of system.
Evacuating System
To achieve the required levels of evacuation, a properly
maintained two stage vacuum pump in good condition is
required. It is absolutely essential to maintain your
vacuum pump according to the manufacturer’s
instructions including required oil changes at the
recommended intervals. Vacuum pump oil should always
be changed after evacuating a contaminated system.
Vacuum pump performance should be checked
periodically with a micron gauge.
1. Make certain that charging cylinder valve, hand
shut-off valve, and manifold gauge valves are all
closed.
2. Start vacuum pump.
3. Open hand shut-off valve and slowly open both
manifold valves, turning counterclockwise, for two full
rotations.
4. Operate vacuum pump for a minimum of 30 minutes
to a minimum of 29.9” (500 micron) vacuum.
5. Close hand shut-off valve to vacuum pump. Watch
compound gauge for several minutes. If reading
rises, there is a leak in the system, go to step 6. If
no leak is indicated, stop vacuum pump. System is
now ready for charging.
6. If a leak is indicated, stop vacuum pump and
introduce a small charge of refrigerant into system
by cracking valve on bottom of charging cylinder until
system is pressurized to 40 or 50 lbs psi.
7. Leak test low-side. Close compound gauge. Run
compressor for a few minutes and leak test
high-side. When leak is found, recapture refrigerant
using EPA approved recovery system. Repair and
go back to step 1.
R-134A SYSTEMS ARE PARTICULARLY
SUSCEPTIBLE TO MOISTURE CONTAMINATION
WHICH CAN ONLY BE PREVENTED BY
EVACUATING THE SYSTEM FOR A MINIMUM OF 30
MINUTES TO ATTAIN A MINIMUM 29.9 INCH (500
MICRON OR LOWER) VACUUM.
If high vacuum equipment is used, just crack
both manifold valves for a few minutes and
then open slowly for the two full turns counter-
clockwise. This will prevent the compressor oil
from foaming and being drawn into vacuum pump.