Temperature Differential between Eric's Thermometer and Brew Temperature - Page 4

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erics
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#31: Post by erics »

Then, this conversation can go on "ad infinitum". When I suggest something, like lowering your boiler pressure to 1.10 bar max, you come back with another question.

My suggestions are an attempt to take advantage of your apparent reduced restrictor size and enable you to brew with minimal flushing.
Skål,

Eric S.
http://users.rcn.com/erics/
E-mail: erics at rcn dot com

Madrooter (original poster)
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#32: Post by Madrooter (original poster) »

Solved: by turning the Pstat up and using long flush and wait.

Turning the Pstat down to 1.1 made the recovery time interminably long. I've now ramped the Pstat up to above 1.3, raising the temp and making it possible to use the long flush and wait. The first flush is seriously long, peaking well over 212, and then down to around 192F or so. It now only takes a few minutes to return to 197, which results in a thermometer reading between 201-203 (brew temp measured in the puck at 199-200), and allows subsequent shots.

In practice, flushing to 198 is probably enough to allow a couple of minutes recovery back up to 197.

The wild card left in the mix is the rinse flush. You have to be careful with that otherwise it can shoot the temp right down. Still a work in progress.

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nixter
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#33: Post by nixter »

I had a thread from way back where Eric first surmised that the newer Rockets might have restrictors. On my Giotto Evo I believe my pstat is set to 1.2 and I use a flush and go technique. My idle is about 206. My flush tops out around 213 and then once it backs down to 210 I stop the flush, pop the basket in my naked PF, lock, and pull. Therm reads about 204 initially and falls to about 200 by the 2nd half of the shot.

Madrooter (original poster)
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#34: Post by Madrooter (original poster) replying to nixter »

Mine does have a restrictor. The top thermosyphon tube tapers into a bell end where it nestles into the group head. Can't really say how much that affects the flow rate.

Mine has very similar numbers now, and I can also do the flush and go as you describe but recovery with the second shot is longer. Too long.

The flush & wait is working out quite well, though the massive first flush (at least 300 ml) takes its toll on the tank.

I suspect I might eventually wind the Pstat back down a touch and see how it affects recovery.

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erics
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#35: Post by erics »

Although this is a video about the R58, an assembly line shot at 1:02 shows the restrictor being installed in the top group tube where it connects to the grouphead for the other models.

http://www.wholelattelove.com/videos.cfm?playvidID=554
Skål,

Eric S.
http://users.rcn.com/erics/
E-mail: erics at rcn dot com

Madrooter (original poster)
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#36: Post by Madrooter (original poster) replying to erics »

There's nothing like that on the Premium Pro. The restriction is part of the pipe. It cones into short venturi where it nestles into the head. If you wanted to remove the restriction, you'd need to replace the entire pipe. The other end of the pipe is untapered. As is the return pipe.

We're fortunate there's no flow adjustment on the thermosyphon, otherwise that'd be more weeks out of our lives fiddling.

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