User guide

142 Advanced User Guide
6 Checking for Leaks
To Perform a PTV Pressure Decay Test
The pressure decay test checks for leaks from the inlet flow
module up to the column fitting.
After performing maintenance, first check for leaks in
externally accessible areas. See “To Check for External Leaks”.
If a leak is known to exist, check the externally accessible inlet
fittings first, especially any connection that has seen recent
maintenance, such as the septum nut, column adapter, column
connection, and so forth.
The pressure decay leak test described below requires removing
the column and capping the inlet column fitting. This test
can/cannot find the following types of leaks:
1 Gather the following (see Consumables and parts for the PTV
inlet):
• No- hole ferrule
• 1/4- inch wrench
• Heat- resistant gloves (if the inlet is hot)
• Column nut
• New septum
• New Graphpak 3D ferrule and liner
The test can find leaks at the: The test cannot find leaks at the:
septum column fitting
septum nut gas supply bulkhead fittings to the
flow module
liner O-ring seal tubing and connections in a transfer
line connected to the inlet
gold seal/washer and reducing nut
inlet body
flow manifold split vent valve
flow manifold septum purge valve
split vent tubing and trap
septum purge tubing
seals within the tubing between the
inlet flow module and the inlet body