Espresso mod for water flow adjustment

Equipment doesn't work? Troubleshooting? If you're handy, members can help.
Marco_83

#1: Post by Marco_83 » Jan 12, 2020, 11:34 am

I open this post to centralize all existing methods to modify an espresso coffee machine in order to be able to make flow adjustment in the goal of profiling (manually or by other way more automatizated).

I see the kit proposed for E61 group head where a sort of flow restrictor is added to the mushroom. The variation of flow is not directly visible but a pressure gauge is added for that.
https://coffeeequipmentreviews.wordpres ... valve-kit/
Question for owners of this kit: is it the discharge valve (OPV) which open when the lever of this kit is completely closed (while the pump is not stopped) ?

Thanks to post other possibilities, modifications, kits, ...

Marco_83

#2: Post by Marco_83 » Jan 14, 2020, 6:43 pm

Profiling is not interesting ? :wink:

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yakster
Supporter ♡

#3: Post by yakster » Jan 14, 2020, 7:03 pm

I think other threads exist already for this topic.
-Chris

LMWDP # 272

pcrussell50

#4: Post by pcrussell50 » Jan 14, 2020, 7:46 pm

Marco_83 wrote:Profiling is not interesting ? :wink:
Totally interesting. And for some, essential. It's just that at this early stage of the game, each of us who has achieved it has probably gone about it a different way.

-Peter
LMWDP #553

Marco_83

#5: Post by Marco_83 » Jan 15, 2020, 4:44 am

Hope they come back a moment on HB forum to exchange :D

Nunas
Supporter ♡

#6: Post by Nunas » Jan 15, 2020, 12:28 pm

Question for owners of this kit: is it the discharge valve (OPV) which open when the lever of this kit is completely closed (while the pump is not stopped) ?
Yes. if you have a vibe pump. If you have a rotary then the inbuilt bypass operates. It's the same as using a blind basket or a choked puck.

Marco_83

#7: Post by Marco_83 » Jan 15, 2020, 4:56 pm

Thanks Numas for this clarification.

Is there a risk for the component OPV in case of repeated/long discharge of water (if paddle close, and pump not stopped quickly) ?

I will say not in case of vibration pump, and good quality opv made in brass. But I don't know :|

Nunas
Supporter ♡

#8: Post by Nunas » Jan 15, 2020, 5:46 pm

No, there's no problem. The OPV on a vibe pump is partially open most of the time, as the pumps produce ~15 bar, while the shot requires ~9 bar. The rest is always diverted via the OPV. It's similar to the rotary pump...the bypass is nearly always dong something. I had a plastic OPV in my Magister and only replaced it once because the vibe pump died and I broke the OPV taking it off. This stuff is all made to last for years. The only limitation I can think of isn't the OPV or the bypass. It's the vibe pump. MOst of them have a 50/50 duty cycle with a maximum run time of 60-seconds, more or less. I think the rating is a bit different on the 220-Volt/50-Hertz pumps, but not a lot. The rotary pumps, on the other hand, can run for a long time without failure.

Marco_83

#9: Post by Marco_83 » Jan 15, 2020, 6:04 pm

And rotary pump are really quiet :wink:

So I think I will order a rotary one. On my other post and this one, I read that rotary model integrates a balanced system for 9 bar regulation. If I have well understand, the opv must be maintained (just on pump outlet) to discharge water as a security.

I have just buy this model of opv but there is no information about connection. Do you know how to connect each port ?

Image

JRising

#10: Post by JRising » Jan 16, 2020, 11:37 am

Marco_83 wrote: If I have well understand, the opv must be maintained (just on pump outlet) to discharge water as a security.
I have just buy this model of opv but there is no information about connection. Do you know how to connect each port ?
image
Yes, with a rotary pump, the other OPV is an expansion valve. It is there to prevent the Heat-exchanger or coffee boiler circuit from rupturing when it heats. The inlet has a check valve and the brew valve is closed when it heats up. Without an expansion valve it's like putting a pop can in the bonfire.

Anyway, 2's the pump, 3's the pipe or hose going off to the T-off before Steam Boiler and HX or coffee boiler, 1's the flexible hose back to reservoir (Or drain if plumbed). Yes, Drain if plumbed. Wasting Expansion Valve water, or any water for that matter, keeps coffee grounds flowing and keeps drains from clogging.