My thoughts on adding pre-infusion to La Marzocco Linea - Page 5

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cafeIKE
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#41: Post by cafeIKE »

The sensing circuit connects pin 2 to pin 6. How much trip current is unspecified. As the internals of the control box are unknown, an SPDT relay across the motor pin on the terminal block will properly control the timer start / stop.

PM if you need further clarification of the schematic
http://www.ielogical.com/coffee/LineaPI.pdf

mitch236 (original poster)
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#42: Post by mitch236 (original poster) »

It's working!! I haven't brewed any drinks yet as I have to let the machine get up to temp.

I had to resort to interrupting power to the timer to get it to reset after each activation but I can correct that with an SSR if I decide I need it. The only drawbacks as I can tell would be I have to activate the pump to change settings or see what my setting are. Other than that, I don't see any problems.

My initial pre-infusion time is 10 seconds. I based that on the Hydra which according to Synesso's website, is their pre-infusion time. Of course my setup is a very simplistic version of their's and I have no illusions that I can really compare.

I can't wait for the first shot. Apollo 5.0 is in the grinder!

mitch236 (original poster)
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#43: Post by mitch236 (original poster) »

First shots are great! At 10 seconds, the first drops are showing up and then the pump kicks in. I found I had to add about 3 seconds to my overall shot timing for proper extraction so that works out to 1/3 the pre-infusion time.

I checked the steam boiler autofill and it works fine. It never activates the pump and so takes longer but works nontheless.

Thanks to all that helped along the way and of course, thanks to Jim and Caffe Streets for setting the bar for me!

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tekomino
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#44: Post by tekomino »

Congratulations Mitch, nothing like a mod for machine that makes shots better.

mitch236 (original poster)
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#45: Post by mitch236 (original poster) replying to tekomino »

I'm not convinced anything is better yet! The only benefit I can tell so far is the consistency of my pours are better. They were good before (mostly because of the Robur) but now they seem bullet-proof.

The one thing I've noticed is I've lost some clarity of my shots (if that makes sense). I don't really understand why but it seems like there was more distinct flavors that now seem a little blended. I think a lot more experimentation is in order but I was running out of beans (I'm sure Counter Culture is happy about that!).

I enjoy tinkering and this has added another parameter for me to play with and learn about.

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tekomino
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#46: Post by tekomino »

mitch236 wrote:The one thing I've noticed is I've lost some clarity of my shots (if that makes sense).
Actually it does. I noticed too that with long pre-infusion this indeed happens. My pre-infusion is at most 4-5 seconds.

mitch236 (original poster)
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#47: Post by mitch236 (original poster) »

It's been three weeks with my pre-infusion mod and yesterday, I removed it permanently. I don't really understand why I couldn't get it dialed in but my shots (currently using CC's Cinco de Junio) taste much more interesting and sweet without pre-infusion. Unless I reduced the pre-infusion time to essentially zero, I found the shots flat tasting. I'm sure it could be made to work by someone with a lot of experience but for me, I find it much easier keeping it simple.

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allon
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#48: Post by allon »

erics wrote:This is what Dave Stephens did with his Faema and what Ken Fox did with his La Cimbali. Dave was working with a 240 VAC pump whereas Ken was working with 120 VAC. To properly "break" 240 VAC, you need to interrupt both "hots". That type of delay relay may be a tough find.
I just picked up a Potter & Brumfield CKB-38-70010 on eBay for cheap. There are a number out there for various prices....

These delay on make relays are double-pole, and can handle 1/2HP @ 250V. (@25°C - 100,000 cycles lifetime at full rated load). Settable from 0.1 to 10 seconds.

DATA SHEET

(then again, it's a crapshoot with mechanical relays on the used market...might be shot, might not, but for the price, it'll be fun to play with)

As noted, double pole, so should work with a 240VAC up to 1/2 HP pump, breaking both contacts.
(it should hardly notice my little vibe pump)
LMWDP #331

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