Post By Dimal
Quaha/Imat/Neopolitan portafilter wear problem
I have a Quaha Junior, at least 6 years old, probably more, used very regularly.
Recently it has begun leaking around the group head which I have not been able to stop.
Purchased new seals from reputable Coffee Snobs sponsor so these are not the issue.
What I have noticed, is under normal brewing pressure, the portafilter rotates ever so slightly in the group head, until the seal is broken and leakage starts.
Holding the portafilter in place manually stops the leakage.
I was just wondering if other users have experienced this? Could it be due to wear of either the portafilter or group head, and how do I tell which one to replace? Is there anything else I could do to make the grip tighter?
More than likely mate, the Group Collar is probably worn out and needs to be replaced. They're not too expensive and pretty sure that JetBlack Espresso have them...
Will give that a try.
No worries mate...
When you get the new one fitted, and checked the Group Handle fit etc, you may need to adjust how much force you use to lock the GH into place as the Collar should not wear out that quickly. The GH only needs to be locked in tight enough to prevent leakage past the gasket, any tighter than this just wears things out prematurely...
I love these machines, but it is a shame that unlike many other machines you cannot use a spacer or thicker gasket. Basically the gasket needs to fit in a lip. Unless someone makes a shaped gasket with two heights:
I haven't replaced the group collar yet. While investigating the problem I have been manually holding the portafilter tightly in place to stop any rotation. This works adequately in most instances while pulling a shot and stops leaks.
When back flushing, if the pressure builds up for more than a few seconds, I hear what I imagine is the seal breaking and water spurts out.
(I have had this problem in the past but replacing the group seal and seating it correctly always fixed it).
As it has been long overdue I pulled the machine to bits and gave it a thorough cleaning. While I was at it I replaced the group seal (again), the boiler o-ring, the element o-rings, ran some sealant around the thread on the water outlet pipe, and upgraded my steam thermal switch from the standard 125C to 140C (as an aside, after years of frustration with inconsistent microfoam, this has seen a big improvement).
On reassembly, first results were promising, no small leaks with cold or hot water running through the system, or pressurised with steam.
There was so much baked on crud around the group head I was sure that this was affecting the performance of the group seal. The new group seal now sits snugly up against a clean surface.
However, after reassembling everything I am still finding leaks around the portafilter when pressurised (after 2 seconds backflushing with blind filter basket)- it doesn't matter how tightly I twist the portafilter on. I am a bit stumped why this should still be leaking.
Anyone have any ideas?