60
TK 56433-5-MM-EN
1. Stop the unit and remove some refrigerant with an
approved refrigerant recovery device.
2. Perform a refrigerant level check and repeat the
overcharge test.
3. If the liquid level is low, add refrigerant as follows:
a. Connect a refrigerant tank to the gauge
manifold service line and purge the line.
b. Mid seat the compressor suction service valve.
c. Set the refrigerant tank for liquid removal and
open the hand valve.
d. Operate the unit in high speed cool.
e. Observe the suction pressure and slowly open
the gauge manifold low pressure hand valve to
allow liquid refrigerant to flow into the
compressor suction service valve.
f.
Control the liquid flow so the suction pressure
increases approximately 20 psig (138 kPa).
g. Maintain a discharge pressure of at least 290
psig (2000 kPa) while adding refrigerant.
h. Close the hand valve on the refrigerant tank
when the liquid level approaches the top of the
receiver sight glass.
4. Repeat the overcharge test.
Moisture Indicating Sight Glass
The receiver tank is equipped with a moisture
indicating sight glass. The outer edge of the sight glass
has a colored ring approximately 0.1 in. (2.5 mm) thick.
The color of the ring indicates the moisture content of
the refrigerant, but it is not completely reliable.
•
Green = Dry
•
Chartreuse = Caution
•
Yellow = Wet
Figure 68.
Moisture Indicating Sight Glass
1.
Floating Ball
2.
Colored Ring
A system has to run for at least 15 minutes to change
the color of the indicator ring after the moisture content
of the system has been changed. For example,
evacuating a system to remove the moisture will not
change the color of the indicator ring until the system
has been recharged and then operated for at least 15
minutes.
Refrigerant Leaks
Use a reliable leak detector that is suitable for R-452A
to leak test the refrigeration system. Inspect for signs of
oil leakage, which is the first sign of a leak in the
refrigeration system.
N
No
otte
e:: It is normal for compressor shaft seals to have a
slightly oily film.
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.
Figure 69.
Compressor Oil Sight Glass - Location
1.
Sight Glass
C
Ch
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ecckk C
Co
om
mp
prre
esssso
orr O
Oiill L
Le
ev
ve
ell -- A
Am
mb
biie
en
ntt A
Aiirr T
Te
em
mp
p
A
Ab
bo
ov
ve
e 5
50
0 F
F ((1
10
0 C
C))
1. Install a gauge manifold on the compressor.
2. Operate the unit on cool with a 20 psig (138 kPa)
minimum suction pressure and a 185 psig (1275
kPa) minimum discharge pressure for 15 minutes or
more.
3. 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.
C
Ch
he
ecckk C
Co
om
mp
prre
esssso
orr O
Oiill L
Le
ev
ve
ell -- A
Am
mb
biie
en
ntt A
Aiirr T
Te
em
mp
p
B
Be
ello
ow
w 5
50
0 F
F ((1
10
0 C
C))
1. Run the unit through a complete defrost cycle.
N
No
otte
e:: If the box is empty, you can run the unit on
the heat cycle instead of the defrost cycle.
2. After completing the defrost cycle, run the unit on
cool for ten minutes.
