What the heck is a gicleur-jet for?!? - Page 3

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NinjaTech

#21: Post by NinjaTech »

Yep, stopped by the local hardware store and picked one up last night, along with the necessary expansion tank. I wasn't able to get them put in last night, I had friends show up, but I'll probably try to get that done tonight. Also have one of these (http://www.freshwatersystems.com/p-3884 ... -fnpt.aspx) on order to put right on the espresso machine to drop it down even further.

Billc

#22: Post by Billc »

The gicleur, French for jet. In this case a flow restrictor. Ever heard of re-jetting a carburetor? This was a process of changing an orifice size to restrict the flow of gasoline the piston receives.

In the case of an espresso machine it is a flow restrictor. Or a means of controlling the flow rate of water to the group. The results are all explained above.

The pressure gauge is placed where it is mostly because of history. Most all older machines had multiple group heads all powered by the same pump. Therefore you would have had to have one pressure gauge per group. The pressure gauge started with the steam boiler for the original steam machines. It was used to monitor the actual pressure in the boiler (also the temperature). The pressure gauge was only to measure pressure in the boiler (the lever provided the pressure). When the pump began its use in the espresso world the pressure gauge remained for steam and also for the brew water to monitor basic pressure characteristics. It has remained this way (with a few exceptions) until recently. Probably until the first individual boiler La Marzocco was built in early 2003 (this one had a pressure gauge for each group).

The Breville Dual Boiler machine is probably only the second home espresso machine made to measure actual brew pressure. It is not exact since it is before the 3 way valve and the valve orifice also has a slight pressure drop as water passes through it. But it is pretty close.


BillC

DavidMLewis

#23: Post by DavidMLewis »

Make sure you feed the espresso machine with 3/8" tubing, not 1/4". A rotary pump, in particular, can drop enough pressure across a few feet of 1/4" tubing to cause the pump to cavitate, which doesn't do it any good.

Best,
David

NinjaTech

#24: Post by NinjaTech »

Alright, PRV, and expansion tank are in. Had no water all last night because i forgot one silly fitting and already had the pipes cut up with no hardware stores in my area open that late.. So brilliant planning on my part there. Anyway, was able to get out and get what I needed this morning. For anyone that is interested, the Astoria/CMA technicians manual states the machine is rated for 1.5-5 bar line pressure. Right now its set a hair under 5 bar, and the machines pump is set to raise the pressure about four bar, the pump actually sounds much 'happier' now that is has a bit more of a load on it raising the pressure four bar, instead of 1.

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erics
Supporter ★

#25: Post by erics »

. . . the pump actually sounds much 'happier' now that is has a bit more of a load on it raising the pressure four bar, instead of 1.
It would probably jump out of the machine and give you a kiss if it had to work with an initial pressure of about 2.5 bar. :)

On a slightly more serious note, the boiler fill solenoid valve may very well appreciate something less than ~5.0 bar.
Skål,

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

NinjaTech

#26: Post by NinjaTech »

Hm.. I see some experimenting in my future. Although, dropping the houses pressure any lower than 5 bar is going to start impacting my shower enjoyment in the morning. To constantly run the machine at lower pressure will require it to be on its own secondary PRV. Going from 8 bar to 5 bar already decreased the forcefulness of the water pressure quite noticeably. Its still tolerable now, but any lower and it will start to get irritating. I may try lowering it more temporarily just to see how the machine does, if you guys would be interested I could post some motor current readings and different pressures just to see how line pressure affects current draw. Knowing how these pumps work I would expect current draw to increase as line pressure drops but it might be fun to know how much.

Would anyone be interested in knowing this? If so, let me know.

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erics
Supporter ★

#27: Post by erics »

Then, install a secondary pressure regulating valve such as this - http://www.watts.com/pages/_products_de ... p?pid=3428 - in the supply line to your kitchen. That way, you are covered nicely for the ice maker in the refrigerator and the dishwasher plus the various faucets in that arrangement, not to mention the espresso machine.



Yes, you're right . . . the current draw will be proportional to the delta P across the pump and, to some extent, those curves are available at the pump mfg's website.
Skål,

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

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cannonfodder
Team HB

#28: Post by cannonfodder »

A pump with a balanced bypass will also help minimize changes in pressure but most espresso machines have a max input pressure of 2-4 bar so you need to regulate that mains pressure down anyway.
Dave Stephens