Purge valves springing leaks

[rycar]

Hello,

I've recently run into a problem with two Agilent 1260 LC systems. Both pumps (G7112B & G1312B) have started to have leaky purge valves. I've been burning through gold seals to try and fix the issue, but in no time they both end up leaking at the base of the threading where the purge valve and the holder meet. I've inspected the threading of both the valve and the holder and I don't see any obvious signs of wear. Has anyone experienced this and found a solution? I would rather not use PTFE tape.

[James_Ball]

Are the gold seals flat when you remove them or to they have a crease in them?

If the teflon filter inside the purge valve is not seating in as far as it should it can cause a crease in the gold seal which will prevent it from sealing. If it is leaking, teflon tape on the threads would not fix it.

[pwm]

Could be leaking internally, which is sometimes repairable. Replacing the valve is also common. Pricing isnt too horrendous, considering headaches such as this. They do need some torque to seal, its possible its just not tight enough. Never have needed or would ever recommend taping the threads.

[Consumer Products Guy]

Could be leaking internally, which is sometimes repairable. Replacing the valve is also common. Pricing isnt too horrendous, considering headaches such as this. They do need some torque to seal, its possible its just not tight enough. Never have needed or would ever recommend taping the threads.

From a 4-decade chemist and mechanic:
We always stocked a spare purge valve unit so we could swap one in. We had failures from those occasionally, sometimes the leakage would come out the purge tubing which went to waste, so was out of sight.

PTFE tape is for tapered pipe threads, not for this instance where the gold seal is the real seal.

When I bought our first 1050 unit, purge valve was not yet invented, so one needed to manually disconnect to purge.

[Multidimensional]

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[Multidimensional]

Did you purchase these two HPLC pumps used? If so, the purge valves or pump heads may have been damaged. When properly used, the purge valves should last 20 or more years, but we have seen many cases where individuals have damaged them resulting in leaks that require replacement of the valves (esp from overtightening the valve or because they did not know how to replace the PTFE frit, which you should be doing every month). Proper Training in how to perform the required maintenance will solve this problem. BTW: The older models of the purge valve are the highest quality ones. If possible, look for new old stock when replacing them.