Leaking from needle seat

Troubleshooting steps when any leak is observed in the sampling area:

• Block port 6 of the sampler’s injection valve with a blind nut and perform System Pressure Test using Lab Advisor twice. In the first execution, leave the injection valve in the mainpass position, whereas in the second one, have it in the bypass position (Instrument Control à Method Parameters). In both cases, use the highest possible pressure setting allowed by the pump unit.
• If both test executions pass, the system is leak-tight. Hence, the observed leak should have an external source, such as the needle wash system.
• If both test executions fail, the leak is most likely not in the sampling area. Possible problem sources are the rotor seal, pump head seals, check valves, the purge valve, or the capillary connection between the pump and the sampler.
• If the test fails in the mainpass but passes in the bypass, the source of the leak is in the flow path section enclosed by ports 2 and 5 of the injection valve. Possible problem causes are a worn seat pill or needle tip, a worn rotor or metering seal, not tight capillary connections, or a broken loop capillary.
• If the test fails in the bypass but passes in the mainpass, the two grooves of the rotor seal are interconnected by a channel, causing a cross-port leakage.

Troubleshooting steps when any leak is observed in the sampling area:

• Block port 6 of the sampler’s injection valve with a blind nut and perform System Pressure Test using Lab Advisor twice. In the first execution, leave the injection valve in the mainpass position, whereas in the second one, have it in the bypass position (Instrument Control à Method Parameters). In both cases, use the highest possible pressure setting allowed by the pump unit.
• If both test executions pass, the system is leak-tight. Hence, the observed leak should have an external source, such as the needle wash system.
• If both test executions fail, the leak is most likely not in the sampling area. Possible problem sources are the rotor seal, pump head seals, check valves, the purge valve, or the capillary connection between the pump and the sampler.
• If the test fails in the mainpass but passes in the bypass, the source of the leak is in the flow path section enclosed by ports 2 and 5 of the injection valve. Possible problem causes are a worn seat pill or needle tip, a worn rotor or metering seal, not tight capillary connections, or a broken loop capillary.
• If the test fails in the bypass but passes in the mainpass, the two grooves of the rotor seal are interconnected by a channel, causing a cross-port leakage.

Hi Mighawk, 

Do you have any suggestions to solve a leak from the needle wash system? 

We recently started using the flush port in our 1260 infinity II autosampler, and we have since then observed significant amount of liquid on the needle seat after the needle wash. I cannot find much information about the flush port in the manual, but maybe I should look for something else. We would really like to solve our problem and I hope that you can help us! 

Hi Cecilie,

Could you please provide more information about the nature of this leak event you have observed with your 1260 Infinity II Vialsampler? I would appreciate it if you could send me a couple of photos so that I better understand the situation.

If the leak stems from the needle wash system, these are the potential sources.

• The well, in which the needle is dipped during the wash procedure, has a hole at the bottom. It can happen, for example, when the needle pierces the bottom of the well. If that is the case, the wash solvent can drip onto the seat during the wash procedure. You could remove the wash port as described in the user manual and inspect it for punch marks. If necessary, replace the wash port.
• The solvent line is not correctly connected to the wash port, causing a leak. You could remove the wash port from the sampler. Then, disconnect the solvent line and reconnect it. If necessary, replace the wash port.