Sealed System Diagnostics Tables; Normal Operating Pressures; Pressure Indications - Sub-Zero UC-24 series Service Manual

Under Counter (UC-24) Series

SEALED SYSTEM DIAGNOSTICS TABLES

NORMAL OPERATING PRESSURES TABLE NOTES:
• Only enter the sealed system to check pressures if the Error Code Troubleshooting Guide and General
Troubleshooting Guide could not pinpoint the cause of the temperature problem.
• Always use solder-on process valves when entering the sealed system. Do NOT use bolt-on process valves as
they are prone to leak.
• Whenever servicing the sealed system, the high-side filter-drier MUST be replaced.
• Pressures listed below are not indicative of initial pull down, but rather of a steadily running and properly function-
ing appliance.
• Pressures listed are for reference only, as actual pressure readings may vary because of one or more of the fol-
lowing reasons:
1. Ambient temperatures (Pressures are based on a 70°F (21°C) Ambient).
2. Temperature set-points (Pressures listed below are based on set-points of 0°F (-18°C) in freezers and 38°F
(3°C) in refrigerators)
3. Food load quantity and temperature.
4. Condenser cleanliness.
5. Whether or not one or both refrigeration systems are operating.
6. Gauge calibration.
Model
UC-24B
UC-24C
UC-24R / UC-24RO
If low-side pressure is
NORMAL
LOW
LOW
HIGH
HIGH

NORMAL OPERATING PRESSURES

Normal Low-Side Pressures
0 - 12 psi to 30 - 42 psi
5" Vac - 1 psi to 6 - 12 psi
0 - 12 psi to 30 - 42 psi

PRESSURE INDICATIONS

& high-side pressure is
NORMAL
LOW
HIGH
LOW
HIGH
8-15
Troubleshooting Guides
Normal High-Side Pressures
75 psi to 110 psi
75 psi to 120 psi
75 psi to 110 psi
possible problem is
MECHANICAL
(see General Troubleshooting Guide)
LEAK
RESTRICTION
INEFFICIENT COMPRESSOR
OVER CHARGE
#7003933 - Revision B - November, 2007