I would attack the OPV first and then TEMPORARILY run separate lines back to the tank. That way you can see whether or not the "self-priming" valve is at fault. The self-priming valve is sealed to the pump with an O-ring (IIRC) whereas the fitting which screws into the self-primer is typically sealed with a Loctite type of sealant (1/8" BSPP straight threads) and CAN BE a potential "problem child" upon reassembly.

Hence, the OPV first.

Here is an illustration of the vibe pump Quickmill machines. The illustration of the grouphead is Copyright 2005 by Verna Design.

The Isomac Tea is plumbed a little differently, with the output of the pump going through a braided stainless tube to the priming valve, which is attached to a T that goes to the water tank and at the other end of the T is the OPV. To get to the OPV, I needed to remove the priming valve which was easy to disassemble. I think it was stuck, and after disassembly (it was clean) and reassembly, I could easily push the plunger inside the valve. All reassembled and working so far, although the metal is not back on the Tea yet.

Good news is I do not see water running back through the overflow and pressure builds up in the portafilter and boiler now appears filled. Also, flow from the pump is between 4 and 5 oz. in 25 seconds. Off to try an espresso. It's been a while.

Thanks for all the help on this site.

-Mark

Yippee! I had a good demitasse of espresso last night and a fantastic one this morning. I've always flushed my machine, but was not quick to get the portafilter back in place. Running the water through the portafilter to raise its temperature slightly before removing to add the coffee, and being quick to avoid overheating the water in the HX, and the espresso was better.

Now that my machine is running again, back to roasting an espresso blend. Single origin coffees (Brazil Poco Fundo) are okay) for espresso, but I prefer blends.

Thanks all.

Thanks for the update, glad to hear the mystery is solved.

mark_neuhausen wrote:The Isomac Tea is plumbed a little differently, with the output of the pump going through a braided stainless tube to the priming valve, which is attached to a T that goes to the water tank and at the other end of the T is the OPV. To get to the OPV, I needed to remove the priming valve which was easy to disassemble. I think it was stuck, and after disassembly (it was clean) and reassembly, I could easily push the plunger inside the valve. All reassembled and working so far, although the metal is not back on the Tea yet.

Good news is I do not see water running back through the overflow and pressure builds up in the portafilter and boiler now appears filled. Also, flow from the pump is between 4 and 5 oz. in 25 seconds. Off to try an espresso. It's been a while.

Thanks for all the help on this site.

-Mark

Arggg, I am having what appears to be the same issue, can someone help me? I am not very familiar with these machines but I have had mine for about 4 years, I just replaced the original pump for the Ulka 52 watt one and didn't do it for me, I am guessing I have the same issue as Mark but I am afraid of touching this thing until I get a better understanding of what is the Priming Valve he's referring to.

Can someone be kind enough to help me thru this.

Thanks in advance guys.

Here is what the priming valve looks like in a drawing:

Post a pic of your machine internals and I will point out the priming valve to you.

Thank you Eric, I am guessing is this one?



And for reference the OPV:

And another one:

DOOOOODEEEE, (=Dude)

OMG, this thing is absolutely melted inside, is a piece like rubber right? I tried with whatever lungs I had and nothing, I stuck a very fine screwdriver on the other side to force it out and finally, it was sort of twisted inside.

The whole part is called the "Air Bleeder Valve"

I guess I can't run it without it right?

Update to my problem,

Received my replacement part from Chris's Coffee and as far as I can tell is slightly different from the original.

Installed the part and reassembled the machine and I am happier than a tornado in a trailer park, my problems are gone now.

Now to enjoy my coffee.

Thanks guys.