Subsystem Checkout; Simple Leak Check Using Vacuum And Pump; Detailed Leak Check Using Pressure - Teledyne T200H User Manual

Teledyne API - Model T200H/T200M Operation Manual

7.5. SUBSYSTEM CHECKOUT

7.5.1. SIMPLE LEAK CHECK USING VACUUM AND PUMP

7.5.2. DETAILED LEAK CHECK USING PRESSURE

Note
07270D DCN7141
•
A dirty reaction cell can cause high AutoZero values.
according to Section 6.3.5.
•
Finally, a high HVPS voltage value may cause excess background noise and a high
AZERO value. The HVPS value changes from analyzer to analyzer and could show
nominal values between 450 and 800 V. Check the low-level hardware calibration
of the preamplifier board and, if necessary, recalibrate exactly as described in
Section 13 in order to minimize the HVPS.
The preceding sections of this manual discussed a variety of methods for identifying
possible sources of failures or performance problems within the analyzer. In most cases
this included a list of possible causes and, in some cases, quick solutions or at least a
pointer to the appropriate sections describing them. This section describes how to
determine if a certain component or subsystem is actually the cause of the problem being
investigated.
Leaks are the most common cause of analyzer malfunction. This section presents a
simple leak check, whereas Section 7.5.2 details a more thorough procedure. The
method described here is easy, fast and detects, but does not locate, most leaks. It also
verifies the sample pump condition.
•
Turn the analyzer ON, and allow at least 30 minutes for flows to stabilize.
•
Cap the sample inlet port (cap must be wrench-tight).
•
After several minutes, when the pressures have stabilized, the SAMP (sample
pressure) and the RCEL (vacuum pressure) readings.
•
If both readings are equal to within 10% and less than 10 in-Hg-A, the instrument is
free of large leaks. It is still possible that the instrument has minor leaks.
•
If both readings are < 10 in-Hg-A, the pump is in good condition. A new pump will
create a pressure reading of about 4 in-Hg-A (at sea level).
If a leak cannot be located by the above procedure, obtain a leak checker that contains a
small pump, shut-off valve, and pressure gauge to create both over-pressure and
vacuum. Alternatively, a tank of pressurized gas, with the two stage regulator adjusted
to ≤ 15 psi, a shutoff valve and pressure gauge may be used.
Once tube fittings have been wetted with soap solution under a pressurized
system, do not apply or re-apply vacuum as this will cause soap solution to be
sucked into the instrument, contaminating inside surfaces. Do not exceed 15 psi
when pressurizing the system.
•
Turn OFF power to the instrument and remove the instrument cover.
•
Install a leak checker or a tank of gas (compressed, oil-free air or nitrogen) as
described above on the sample inlet at the rear panel.
•
Disconnect the pump tubing on the outside rear panel and cap the pump port. If
zero/span valves are installed, disconnect the tubing from the zero and span gas
Troubleshooting & Service
Clean the reaction cell
237