Line Integrity Test Option; Pneumatic Overview - Honeywell Vertex M User Manual

8.11 Line Integrity Test Option

Honeywell now offers the optional capability to check for leaks in Vertex M sample lines.
Analyzers equipped with option 1295-0510 detect a pneumatic signal from valves installed at
the end of the sample line. Any leak in the tubing will cause a change in the signal and will be
detected. This test is performed automatically as a line integrity test (LIT). This new test
complements the ability of all Vertex M analyzers to detect blocked sample lines.
The Line Integrity Test Option requires a minimum software revision of 1.21.1 and
configuration of analyzer software by a Honeywell Field Service Engineer.

8.11.1 Pneumatic Overview

The pneumatic design of the Vertex M rack is summarized in Figure 8-47. The Vertex M
analyzer contains eight sample pressure transducers, one for each point. The external tubing is
terminated with a filter and a check valve. The check valve will not permit any flow until a
cracking pressure of about 1.0 in. Hg is applied. (see Note on this section) A leak between the
analyzer and the check valve will result in an increase in pressure at the analyzer.
Before the LIT test can be performed, the Vertex M and the external plumbing must be
characterized. This process involves measuring the sample pressure when the tubes are known
to be leak-free and otherwise correct. It is possible to confirm that a tube is leak-free by
plugging the end and observing the sample flow decrease to zero. During the characterization
process, the Vertex M records the observed sample pressure. Later LIT tests will issue a fault if
the sample pressure increases significantly. Performing the characterization without a leak
check invalidates the LIT.
Note: In this document all pressures are given in inches of mercury. This may be converted to
kilopascals by multiplying by 3.38. Furthermore, all pressures are reported as gauge pressure,
not as vacuum. Using this nomenclature, the effect of a sample line leak is described as a
pressure increase instead of a vacuum decrease.
Figure 8-47. Simplified Pneumatic Schematic
Vertex M 267 User Manual