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Why Reduce Inlet Water Pressure?

Postby DigitalDave on Thu Sep 23, 2010 7:11 pm

I originally hooked up my new La Spaziale with no regulator, 80psi. I have a regulator on order, but won't get it till next week. I read that the pressure input should be 25-60 psi, but do not understand why. Will I hurt the machine or pump by connecting it this way for a short time, or is this a completely newbie mistake that will cost me? Can someone explain this to me?
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Postby wookie on Thu Sep 23, 2010 7:59 pm

DigitalDave wrote:I originally hooked up my new LaSpaziale with no regulator, 80psi. ... I read that the pressure input should be 25-60 psi, but do not understand why. Will I hurt the machine or pump by connecting it this way

Proceed at your own peril. If you have a scale that says max 200 lbs and you put 250 lbs on it will you damage it? Maybe. We don't really have enough information to know for certain. The manufacturer set a limit because the parts are not assured to support a larger load. Put 250 lbs on it and you may squeak by or you may break it.

Your machine probably uses solenoids, pump seals or whatever that are rated for 60 or 75 psi. At a guess your rotary pump was designed for a maximum 4 bar differential pressure. Feed 80 psi into it and you might still be okay. Or you may have water leaks or damage your pump. Since you don't seem to have a detailed engineering specification we don't know anything other than it is bad practice to ignore the design limits.

Water regulators are not expensive, why risk damaging your machine? You had started another thread asking why your pump wasn't working, but you didn't mention the information about the regulator in that thread.

.
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Postby DigitalDave on Thu Sep 23, 2010 9:06 pm

Water regulators are not expensive, why risk damaging your machine? You had started another thread asking why your pump wasn't working, but you didn't mention the information about the regulator in that thread

Didn't realize it until after the fact... Found comments here and there regarding inlet pressure needing to be reduced, found instructions for other machines saying to reduce to a max of 5bar (75psi?), and I know my water pressure is above that.

OK, I have a regulator, filters, & fittings on order. Guess I'll have to wait. You know, I had an older, experienced friend who just passed. I would be doing a project, and I'd say "Earl, I'm going to do it like this." He'd say "You could do it like that" Time passed and some of those projects didn't work out so well. On the repair of one, I asked Earl what I needed to do to fix it. He told me something quite different from the way I had originally done it. I say "Earl, why didn't you tell me that in the first place?" He says, "Well, you didn't ask my advice. You asked if it would work. And it worked, for a while. If you had asked my advice, I would have told you the right way to do it". So, now you see that maybe I have only learned enough to ask, and I will take your advice. But, you know, I could do it like that! :) Thanks for the advice. Really.
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Postby CremaCrazy on Fri Sep 24, 2010 11:20 pm

Me too!!!

But seriously, I don't know what my line pressure is either. I'm inclined to get a pressure reducer as well. Please let me know what you went with, and where you got it. I'll go try to figure out if there is a "one size fits all" for my application since I don't know pressure I currently have.

I am hoping to keep from destroying what is probably a great machine myself.


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Postby DigitalDave on Sat Sep 25, 2010 9:04 am

Sean,

I ordered this from Chris Coffee:
http://www.chriscoffee.com/products/home/plumbing/regulatorvalve
Won't have it till the middle of next week, will come back & tell you how it went. Note that is has "John Guest" fittings. When I plumbed into my water supply, I originally used "normal" fittings. Well, I redid it using these fittings and it took longer to remove the original stuff than to re-do with these simple fittings. Absolutely easy and no leaks, and they come apart easily and can be reused. I was amazed.
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Postby keepitsimple on Sat Sep 25, 2010 9:45 am

Hello, Digitaldave

A pressure regulator is a bit more sophisticated than just being a pressure reducer. Within its design limits it will also stabilise the output pressure not just reduce it. This is important if you have the type of pump which just "adds" pressure to the incoming supply. You want the output of the pump to remain constant even if upstream of your machine the pressure is reduced because the dishwasher decides to take a drink or someone turns on a tap (faucet).
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Postby Whale on Sat Sep 25, 2010 11:12 am

keepitsimple wrote:...This is important if you have the type of pump which just "adds" pressure to the incoming supply. You want the output of the pump to remain constant even if upstream of your machine the pressure is reduced because the dishwasher decides to take a drink or someone turns on a tap (faucet).


I agree with the above to a certain degree but since the OP is hooking up a La Spaziale, the machine has a rotary pump that delivers a lot more flow than comes out from the group when brewing. Thus the pressure at the group is controlled internally by the pressure setting at the pump (a spring loaded by-pass conduit).

Although, there might be a pressure recommendation for the machine, it is probably more important for performance than machine limitation. The line water plumbs in the pump directly and everything downstream of the pump will be subjected to pretty much 9 bars (130 psi) or so. Personally I do not think that internal damage could ensue from being hooked up to 80 psi in line pressure.

Where it makes a huge difference is in the performance of pre-infusion that relies on line pressure only (La Spaziale Vivaldi). The stability and pressure level are very important parameters in this feature. Pre-infusing at 80 psi with the possibility of variation is a recipe for bad extraction in my opinion.

I have my inlet pressure regulated at 25 psi using 8 seconds pre-infusion. Works good for me. Just a vaguely educated recommendation. YMMV.
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Postby JohnB. on Sat Sep 25, 2010 11:38 am

Whale wrote:I agree with the above to a certain degree but since the OP is hooking up a La Spaziale, the machine has a rotary pump that delivers a lot more flow than comes out from the group when brewing. Thus the pressure at the group is controlled internally by the pressure setting at the pump (a spring loaded by-pass conduit).

I have my inlet pressure regulated at 25 psi using 8 seconds pre-infusion. Works good for me. Just a vaguely educated recommendation. YMMV.


If you set the group pressure to 9b with a line pressure of say 45psi & the line pressure drops or increases your group pressure will also drop or increase. The accuracy of your setting is dependent on maintaining a fixed line pressure, thus the need for a pressure regulator.

As for your 25psi line pressure I would consider that pretty low for the S1V2's line pressure p/i. 3Bar seems to be the ideal to shoot for & since you are limited to a set p/i time would certainly be more effective then 25psi. If you had full manual p/i then 25psi would work ok "eventually" but with the Vivaldi I would turn up your line pressure if possible.
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Postby Whale on Sun Sep 26, 2010 9:48 am

JohnB. wrote:If you set the group pressure to 9b with a line pressure of say 45psi & the line pressure drops or increases your group pressure will also drop or increase. The accuracy of your setting is dependent on maintaining a fixed line pressure, thus the need for a pressure regulator.


Hello John.

As I wrote the Vivaldi, and pretty much all other rotary pump machine, have a by-pass conduit that one can adjust to control pressure. This is a regulator! I do not think that having another regulator upstream would increase the stability of the group pressure in a significant way. This is just an opinion that I have not experimented.

JohnB. wrote:As for your 25psi line pressure I would consider that pretty low for the S1V2's line pressure p/i. 3Bar seems to be the ideal to shoot for & since you are limited to a set p/i time would certainly be more effective then 25psi. If you had full manual p/i then 25psi would work ok "eventually" but with the Vivaldi I would turn up your line pressure if possible.


For the pre-infusion pressure, which is the real reason for having a pressure regulator (for me at least), to be precise, my regulated setting is 28 psi dynamic (30 psi static). I went under the sink to verify. I am sorry for not having more precise in the first post. :oops:

This is something that I have investigated extensively and found this to be the best set point for me and my usage.
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Postby SwingT on Sun Sep 26, 2010 11:16 am

I don't have the time and inclination to experiment as much as many posters here, and even if I did - my system and stomach just can't handle very much espresso -

I've got the regulater/reducer from Chris - in addition to having a larger one for my whole house. The pressure here is ways high, so I had the plumber put in a pressure regulator on the main - years ago.

Having said that - I finally got my S1V2 tasting a lot more like my Cremina (which I prefer) and happened to look under the counter and see the gauge ( which I got from Chris at the same time) while pulling a shot - was at 22 psi, which was a surprise - I last set it at around 35. The incoming pressure changed and/or the larger pressure regulator shifted it's band of operation - anyhow something shifted.

22 lbs is lower than most will recommend - but sure tastes nice to me - obviously, individual tastes and preferences can be markedly different.

Even so, works beautifully for me.
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