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Teledyne API T801 NDIR CO2 Analyzer Operation Manual Maintenance Schedule & Procedures
177
10.3.3. PERFORMING LEAK CHECKS
Leaks are the most common cause of analyzer malfunction; Section 10.3.3.1
presents a simple leak check procedure. Section 10.3.3.2 details a more thorough
procedure.
10.3.3.1. VACUUM LEAK CHECK AND PUMP CHECK
This m
ethod is easy and fast. It detects, but does not locate most leaks. It also
verifies that the sample pump is in good condition.
1. Turn the analyzer ON, and allow enough time for flows to stabilize.
2. Cap the SAMPLE inlet port.
3. After several minutes, when the pressures have stabilized, note the following.
In the TEST menu, note the SAMPLE PRESSURE reading.
4. If the reading is < 15 in-Hg, the pump is in good condition and there are no
large leaks.
5. Check the sample gas flow. If the flow is <10 cm
3
/min and stable, there are
no large leaks in the instrument’s pneumatics.
10.3.3.2. PRESSURE LEAK CHECK
If you can’t locate the leak by the above procedure, use the following procedure.
Obtain a leak checker similar to the Teledyne API PN 01960, which contains a
small pump, shut-off valve and pressure gauge. Alternatively, a convenient
source of low-pressure gas is a tank of span gas, with the two-stage regulator
adjusted to less than 15 psi with a shutoff valve and pressure gauge.
CAUTION
GENERAL SAFETY HAZARD
Do not use bubble solution with vacuum applied to the analyzer. The solution may
contaminate the instrument. Do not exceed 15 PSI pressure.
1. Turn OFF power to the instrument.
2. Install a leak checker or tank of gas as described above on the SAMPLE inlet
at the rear panel.
3. Remove the instrument cover and locate the inlet side of the sample pump.
Remove the flow assembly from the pump and plug it with the appropriate
gas-tight fitting.
4. Pressurize the instrument with the leak checker, allowing enough time to fully
pressurize the instrument through the critical flow orifice. Do not exceed 15
psi pressure. Check each fitting with soap bubble solution, looking for
bubbles. Once the fittings have been wetted with soap solution, do not re-
apply vacuum, as it will suck soap solution into the instrument and
contaminate it. Wipe down and thoroughly dry all parts first.
5. Once the leak has been located and repaired, the leak-down rate should be
< 1 in-Hg (0.4 psi) in 5 minutes after the pressure is shut off.
07274B DCN6418