Zodiaco Lambro President flow control mod. - Page 2

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Postby okmed » Jan 11, 2018, 10:57 am

NelisB wrote:Because the spring is pushing back the flow of the water coming from the boiler. The pressure in the boiler is already too low to do a full pre-infusion. My thoughts is that a static resistor will give a more constant flow.

...Please correct me when I am wrong... :roll:

The video by bakafish shows how adjusting the spring tension adjusts the flow (and allows the check valve function to remain).

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Postby vberch » Jan 11, 2018, 11:48 am

I had a leak from a worn o-ring as well. That gave me an opportunity to take it apart, clean it and make it as new again. In my case it was a combination of an o-ring and gasket at the top. Using the valve, preinfusion is adjusted from a very slow drip (or can be turned to no flow at all) to a gusher.



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Postby NelisB » Jan 13, 2018, 6:33 am

bakafish wrote:Why mod? It is adjustable.

I know. I even used it as a paddle: first close it all the way, then put the lever down, then open the rod a little and if I didnt hear the water flow anymore, open it all the way till the coffee starts dripping, then releasing the lever slowly.

But I don't think the low flow with the ball almost up is very constant. With the static restrictor (and no spring) it seems more constant. The spring gives a force to the water flow, making it a dynamic system.

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Postby samuellaw178 » Jan 13, 2018, 7:03 am

Hi Niels,

That looks really good. What's the flow rate you're getting/aiming for, is it adjustable? I tried reducing the flow rate (low tech mod) on my lever too for curiosity. :D At one point I went too far and it took more than 15 sec to fill the chamber. :? Shots seem to suffer in body with such dragged out preinfusion. But I have now settled at a flow rate that fills the chamber in ~3 sec (for a 10 sec preinfusion) and haven't adjust much since (it's non adjustable so really labor intensive to change).

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Postby NelisB » replying to samuellaw178 » Jan 13, 2018, 7:50 am

No it is not adjustable.
How did you do your low tech mod?
I still have a way too long pre-infusion. Lack of pressure I think. How much is your boiler pressure?

Team HB

Postby samuellaw178 » replying to NelisB » Jan 13, 2018, 7:19 pm

It was really crude. :oops:

I've done it two ways. One was by using a copper sheet sandwiched in a 1/4" pipe connector and a lock nut, to make a 'gicleur' that goes into the group head inlet port (originally meant for a dipper tube but my lever doesn't use the dipper port). The copper sheet was easy to work with because I can cut to size and punch a hole instead of drilling. No workshop access here. But to change that I have to remove the entire group head each time. :oops:

Second method : My lever group has a non-adjustable springless ball valve. So I've added some silicone sheet spacer above the stainless ball to restrict the ball movement (thus restricting the flow). In either case, it's really trial and error to find the flow rate that works.

Mine is a HX-lever that uses the water line (about 2.5-2.7 bar). But in both methods I don't find the preinfusion pressure being reduced, as long as the chamber is filled with water.