8
1. It is recommended the manifold be opened to
the atmosphere before every working session.
If display reads other than zero in the selected
pressure units, zero can be re-set by pressing
and holding [CLR] at main screen. The Pressure
Zero Screen [FIG.7] appears and will then
return user to Main Screen [FIG.1], where
both Pressure Displays should now read zero.
This operation should be performed especially
if manifold has been dropped or pressurized
beyond 800 PSIG (55 bar) full scale.
SETTING TO ZERO PRESSURE
Pressure Zero Screen
APO
FIG.7
PRESSURE HOLD TEST
A pressure hold test should be used to determine if a large leak exists (not to determine
if no leak or small leaks exist). Electronic Leak Detectors are the only instrument to
determine leak rates less than 1 oz./year. In practice there should be no pressure hold
detected if the system is deemed leak proof enough to add refrigerant. Large leaks
should be found before adding refrigerant. Low cost tracer gas mixtures such as 95%
N2 and 5% H2 are popular and can be sensed by a CPS E_MOS leak detector.
1. At Main Screen [FIG.1] press [TEST]. The Test Pressure Set Screen will appear
[FIG.8]. [Note: The MDXVG Vacuum Gauge accessory should not be plugged in
at this time].
2. Press [SET] to advance to Test Time (Pressure) Set Screen [FIG.9].
Test Pressure Set Screen
APO
FIG.8
hh : mm
APO
Test Time Pressure Set Screen
Adjust Test
Duration In 5
Minute Increments
FIG.9
PRESSURE HOLD OR VACUUM HOLD TESTING
The BLACKMAX MD100 and MD50 series manifold can perform Pressure Hold and
Vacuum Hold tests. Test pressures and durations are fully settable by the user. Any
test can be aborted at any time by pressing [CLR].
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