Page 13
6-13
SEALED SYSTEM DIAGNOSTIC INFORMATION
NOTE:
The temperature/pressure table at right is for refer-
ence only. A unit's temperature/pressure correlation may
differ from those listed due to: variations in evaporator ther-
mistor location, set-points, where the sealed system is in
the refrigeration cycle, ambient temperature, etc.
If a unit is experiencing temperature problems, it is recom-
mended to reference the Error Code Troubleshooting Guide
and General Troubleshooting Guide before accessing the
sealed system. After all mechanical and electrical compo-
nents have been ruled out, sealed system pressures can
be checked and compared against those listed in the tables
below.
NOTE:
Whenever entering the sealed system, always use
solder-on process valves. Do
NOT
use bolt-on process
valves as they are prone to leak.
NOTE:
Whenever servicing the sealed system, the valve
assembly (includes high-side filter-drier) must be replaced.
NORMAL OPERATING PRESSURES
Model
424
Normal Low Side Pressures
10 psi to 36 psi
Normal High Side Pressures
90 psi to 100 psi
PRESSURE INDICATIONS
If low side pressure is
NORMAL
LOW
LOW
HIGH
HIGH
& high side pressure is
NORMAL
LOW
HIGH
LOW
HIGH
possible problem is
MECHANICAL
(see General Troubleshooting Guide)
LEAK
RESTRICTION
INEFFICIENT COMPRESSOR
OVER CHARGE
Pressure
10” Vac / -.69 Bar
7” Vac / -.48 Bar
4” Vac / -.28 Bar
0” Vac / 0 Bar
2 Psi / .14 Bar
4 Psi / .28 Bar
7 Psi / .48 Bar
9 Psi / .62 Bar
12 Psi / .83 Bar
15 Psi / 1.03 Bar
18 Psi / 1.24 Bar
22 Psi / 1.51 Bar
26 Psi / 1.79 Bar
30 Psi / 2.07 Bar
35 Psi / 2.41 Bar
40 Psi / 2.76 Bar
45 Psi / 3.10 Bar
51 Psi / 3.52 Bar
57 Psi / 3.93 Bar
64 Psi / 4.41 Bar
71 Psi / 4.90 Bar
78 Psi / 5.38 Bar
Temperature
-30°F / -34°C
-25°F / -32°C
-20°F / -29°C
-15°F / -26°C
-10°F / -23°C
-5°F / -21°C
0°F / -18°C
5°F / -15°C
10°F / -12°C
15°F / -9°C
20°F / -7°C
25°F / -4°C
30°F / -1°C
35°F / 2°C
40°F / 4°C
45°F / 7°C
50°F / 10°C
55°F / 13°C
60°F / 16°C
65°F / 18°C
70°F / 21°C
75°F / 24°C
TEMPERA
TURE / LOW
-SIDE PRESSURE CORRELA
TION
#7031933 - Revision A - April, 2015
MODEL 424
MODEL 424
(SWS #3227000)
(SWS #3227000)
Troubleshooting Guides
