Checking for External Leaks on 7697A Headspace

Answer

This Information Applies To: Agilent 7697A Headspace Sampler

Issue:

There is a potential leak external to the Headspace unit that can cause loss of pressure.

Steps to Follow:

This article is a troubleshooting guide for when you suspect there is an external leak in the headspace sampler (HS) when it is installed on the inlet of a GC. (Figure 1)

Figure 1: External Leaks can occur in multiple locations: Gas supply bulkhead fittings, Gas cylinder fittings, Regulator fittings, Traps, Shut- off valves (if installed, not included in ship kit), Unions and tee fittings (if installed, not included in ship kit), transfer line connection to the GC

Warning: A pressure decay test cuts off carrier flow through the HS and GC. To prevent damage to the flow path components (column, inlet liner, and so forth), cool the HS and GC before beginning.

1. Cool the HS sample loop, transfer line, and GC inlet and column oven to prevent damage during the test.
2. Turn off the HS.
3. Set the regulator pressure to 415 kPa (60 psi).
4. Fully turn the regulator pressure adjustment knob counterclockwise to shut the valve.
5. Wait 5 min.
   1. If there is a measurable drop in pressure, there is a leak in the connections or an internal leak. Utilize a leak detector to locate any external leaks. 
   2. No drop in pressure indicates that the external connections are not leaking 

Learn how to effectively maintain your 7697A Headspace Sampler: SI-7697-2100sV3 - Agilent 7697A Headspace Sampler Operation and Maintenance e-learning available from Agilent education.