Models 947, 948 and 960 Leak Detectors Operations and Service Manual
3-10
3.3.1 Startup Procedure
To perform the start-up procedure:
1. Locate the main power switch/circuit breaker
➀
on the back of the lower cabinet and
turn it on.
2. Turn on the Rough
➁
pump switch.
3. Turn on the Detector
➂
switch.
4.
Models 948/960 only:
When the system pressure bar graph drops into the green range
(see Figure 1-3 on page 1-6),
fill the cold trap with liquid nitrogen.
WARNING
Liquid nitrogen causes burns upon contact. Use appropriate
protective devices, including heavy loose gloves and eye or
face shields.
Refill the cold trap as required to prevent it from thawing in the vacuum system. The
trap needs to be filled approximately every 14 hours. Monitor the level and fill more
often if necessary.
CAUTION
If the cold trap in the 948/960 is allowed to empty of liquid and
thaw in the vacuum system, spectrometer tube contamination
occurs resulting in unstable leak rate detection. Attempts to
perform an automated calibration can also result in error
conditions (codes c6, c7, and c8). Filling the trap completely
keeps the trap operational up to 14 hours. Before refilling is
required, refer to Section 4, “Maintenance” on page 4-1 for the
cold trap cleaning procedure.
5. Wait 30 minutes for the 947/948/960 to warm up to operating temperature.
6. The detector is now on and ready for normal operation.
NOTE
Perform the calibration and sensitivity check before taking
readings with the 947/948/960.
Summary of Contents for 948
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