Thermo King MD-MT, Operator'S Manual

Page: 108 / 192

Refrigeration Maintenance
108
Refrigerant Leaks
Use a reliable leak detector (e.g., electronic
detector) to leak test the refrigeration system.
Inspect for signs of oil leakage which is the first
sign of a leak in the refrigeration system.
NOTE: It is normal for compressor shaft seals to
have a slightly oily film.
NOTE: Electrical controls must be set up as
described in Electrical Controls Setup section
throughout this procedure.
1. Connect leak test gas (R-404A) supply to
center hose of gauge manifold.
2. Attach gauge manifold hoses to suction and
discharge service valves.
3. Open suction and discharge valves and
pressurize system with leak test gas. If desired
system pressure may be boosted using
nitrogen gas.
4. Check connections made during installation
for leaks using a electronic leak detector
and/or soap bubbles.
5. Recover test gas pressure to repair leaks.
System must be vented while repairing solder
joint leaks. Pressurize system and check again
after a leak has been repaired.
6. If no leaks are found, recover test gas to 0 psi.
Checking Compressor Oil
The compressor oil should be checked when there
is evidence of oil loss (oil leaks) or when
components in the refrigeration system have been
removed for service or replacement.
To check compressor oil level with an ambient air
temperature above 50 F (10 C):
Install a gauge
manifold on the compressor.
R-404A and R-502 Systems—Operate the unit on
Cool with a 18 psig (124 kPa) minimum suction
pressure and 185 psig (1275 kPa) minimum
discharge pressure for 15 minutes or more.
After the unit has maintained the above conditions
for 15 minutes, observe the oil level. The oil
should be 1/4 to 1/2 up in the sight glass.
CAUTION: Oil is under pressure. See
instructions for adding oil.
1. Add Compressor Oil Here
2. Oil Level Sight Glass
3. Drain Screw
Figure 58: X214 Compressor