Zodiaco Lambro President flow control mod.

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NelisB

Postby NelisB » Jan 10, 2018, 3:05 pm

I guess most Lambro and President owners know this kind of water output from the Zodiaco group.


I think less initial water will give a slower and better pre-infusion.
So I replaced the ball and inner spring of the (flow control?-) assembly at the bottom of the group with a static flow resistor that I had made. It should have been drilled with a 0.6mm drill, but the drill broke, so 1.0mm was used.

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With the resistor this is the result:


What do you think?

Paolo

Postby Paolo » Jan 10, 2018, 3:27 pm

Hi Niels,
From the videos, the flow looks much smoother and better controlled. Well done!

Have you noticed any difference in the quality of the shots?

Ellejaycafe

Postby Ellejaycafe » Jan 10, 2018, 3:30 pm

I always suspected the flow rate is much lower when pulling a shot.... the resistance of the ground coffee doesn't allow the water to simply explode out of the group. I could be completely wrong.

On my modern lever group you can close the valve on the back to restrict the flow like shown in your second video. I tried it a couple of times and never noticed a big difference honestly.
LMWDP #544

okmed

Postby okmed » Jan 10, 2018, 4:13 pm

Without the check valve function are you not concerned about water backing up into the boiler until the piston travels enough to block off the inlet opening on the cylinder wall ?

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NelisB

Postby NelisB » Jan 10, 2018, 4:15 pm

Ellejaycafe wrote:I always suspected the flow rate is much lower when pulling a shot.... the resistance of the ground coffee doesn't allow the water to simply explode out of the group. I could be completely wrong.

The ground coffee needs water to build up resistance. So resistance will start off being zero. As soon as the ground coffee saturates the flow will slow down.

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NelisB

Postby NelisB » Jan 10, 2018, 4:18 pm

okmed wrote:Without the check valve function are you not concerned about water backing up into the boiler until the piston travels enough to block off the inlet opening on the cylinder wall ?


That would be as you let the lever up, building up pressure, but before blocking the inlet opening?

bakafish

Postby bakafish » Jan 10, 2018, 9:59 pm

Why mod? It is adjustable.

okmed

Postby okmed » Jan 11, 2018, 12:22 am

NelisB wrote:That would be as you let the lever up, building up pressure, but before blocking the inlet opening?


Yes, that's correct.

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NelisB

Postby NelisB » Jan 11, 2018, 4:37 am

bakafish wrote:Why mod? It is adjustable.


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:

bakafish

Postby bakafish » Jan 11, 2018, 10:40 am

NelisB wrote:Because the spring is pushing back the flow of the water coming from the boiler.

I ever had a leak issue due to the o-ring broken on the brass screw in your first image. The o-ring position is inside the chrom plating part. That means the chamber where the spring at is full of water, so I don't think the spring can be compressed by the boiler pressure, and it cannot push back the flow either. The steel ball does not touch the o-ring above it in the group though I think it should.
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