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During the pressure decay test, Pc will adjust as the current system pressure changes. Pi-Pc will
adjust to reflect the change between the initial system pressure and current system pressure.
Limit will display the limit pressure as determined by the percent allowable change. System
pressure dropping below this value within the time limit as set by the test duration will trigger a
failure. The rate of change as denoted by %/min displays the percent change in system pressure
per minute. A large leak will be indicated by a larger %/min value, conversely a smaller %/min
indicates a small system leak.
If the system pressure falls below the limit pressure within the test time limits, the P51-870
TITAN® will display a “FAIL” notice (Figure 24) and the buzzer will sound indicating the test is
complete. To silence the buzzer, exit the pressure decay test by selecting the modes button. If
the pressure decay test ends before the system pressure falls below the limit pressure, the device
will display a “PASS” notice and the buzzer will sound indicating the test is complete (Figure 25).
Pressure Hold Mode - Pressure Rise Test
Overview:
Pressure hold mode can also be used to monitor the system for a rise in vacuum pressure. A
pressure rise test can be helpful to determine if the system has a leak or there are non-
condensables and refrigerant remaining within the system. The pressure rise test displays the
current system vacuum pressure (Pvac), the percent change per minute (%/min), the initial
pressure (Pi), the Limit pressure and test duration.
Figure 24: Pressure Decay Test - FAIL
Figure 25: Pressure Decay Test - PASS
Summary of Contents for 40870
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