I'm converting to a rotary pump for my Expobar. I've read a bunch of past posts and done some research, but I still have a few questions.

The pump will be under the counter, fed with filtered water at house pressure of about 45 psi. Pump is a ProCon model 112A060F11CB130 (a rebuilt one, from some nice people at JC Beverage Co. in Minnesota for $58.50). Motor is 1/4 HP small one from EPNW, on the expensive side, but fitting my space.

I spoke to an engineer at ProCon, and here are a few factoids (according to him) I hadn't found definitively elsewhere:
(1) the 060 in the model number is a gallon-per-hour specification and is way more than needed, however as long as it's enough it doesn't matter, the pump won't waste anything, heat up, or wear more because of excess capacity.
(2) pressure is adjustable, within range, and is insensitive to input pressure, as long as flow is sufficient.
(3) the CB in the spec is what ProCon recommends for espresso, although JC Beverage is used to supplying DB. CB is also what EPNW sells in their new pumps (however theirs have 3/8 BSP ports instead of 3/8 NPT as mine has).
(4) Yes, the input pressure will appear at the output when the pump is not running. Presumably could be used for boiler fill and pre-infusion.
Not tested yet, but I think all that is correct.

Questions:
(1) Solenoid -- Do I need (should I include) a solenoid valve. I have a manual shutoff for maintenance, etc. Maybe a solenoid is a good idea, in case my tinkering leaves a flakey joint some time. OK to have it on with machine power? Or if just with the pump? Should it be before or after the pump?
(2) Regulator -- Do I need one? Some comments have suggested that brew pressure can be adjusted by varying a regulator on the input side of the pump (contradicted by the ProCon engineer). I'll be easily able to access the adjustment on the pump.
(3) OPV -- I'm planning to install the Expobar's OPV, under the counter, in line fed from the output of the Procon, as a safety with the pressure set up above the brew range.
(4) check valve -- Someone recommended having one, in the machine I think, to prevent draining water if the machine is disconnected. Is there any other reason?
(5) I plan to use John Guest 1/4" tubing from pump to machine, except for a short braided hose above the counter. Any reason to use anything else? How about JG quick-connects? Are they OK for brew pressures?
(6) Is there any problem or consequence to having the Hx pressurized during idle times? I just installed a brew pressure gauge, and I find that if I don't release it, the brew pressure stays in the thermosyphon circuit for quite some time. Presumably, the house line pressure would be there all the time if no solenoid is fitted, or if it stays on when the machine is powered up. I don't understand boiler dynamics enough to have a sense if this would affect thermosyphon action or whatever.

Well, if you read this far, many thanks. More still if you help me on any of these questions.

DickC wrote:I'm converting to a rotary pump for my Expobar. I've read a bunch of past posts and done some research, but I still have a few questions.

The pump will be under the counter, fed with filtered water at house pressure of about 45 psi. Pump is a ProCon model 112A060F11CB130 (a rebuilt one, from some nice people at JC Beverage Co. in Minnesota for $58.50). Motor is 1/4 HP small one from EPNW, on the expensive side, but fitting my space.

I spoke to an engineer at ProCon, and here are a few factoids (according to him) I hadn't found definitively elsewhere:
(1) the 060 in the model number is a gallon-per-hour specification and is way more than needed, however as long as it's enough it doesn't matter, the pump won't waste anything, heat up, or wear more because of excess capacity.
(2) pressure is adjustable, within range, and is insensitive to input pressure, as long as flow is sufficient.
(3) the CB in the spec is what ProCon recommends for espresso, although JC Beverage is used to supplying DB. CB is also what EPNW sells in their new pumps (however theirs have 3/8 BSP ports instead of 3/8 NPT as mine has).
(4) Yes, the input pressure will appear at the output when the pump is not running. Presumably could be used for boiler fill and pre-infusion.
Not tested yet, but I think all that is correct.

Dick, here's a link at Procon that explains all those characters in the part number, Procon Standard Series Model Number Matrix.

Can you adjust the pressure or is it preset on that particular pump you have there? Can you post a picture? I am just curious.

FWIW, I just pulled a rotary pump (different manufacturer) rated at 600 LITERS per hour (~160gph), so I guess that can vary a good bit! This one also has the balanced bypass like yours.

Questions:
(1) Solenoid -- Do I need (should I include) a solenoid valve. I have a manual shutoff for maintenance, etc. Maybe a solenoid is a good idea, in case my tinkering leaves a flakey joint some time. OK to have it on with machine power? Or if just with the pump? Should it be before or after the pump?

Well, you'll need a relay to turn on the pump, might be a good idea to open a solenoid as well at the same time if one does not already exist in your brew circuit. A normally closed valve may help you sleep better. That said, it should not be needed. But, if you want to mess with mains pressure preinfusion, leave it out (but add the regulator). See Is there a purpose for the E61 middle brew lever position? for details.

(2) Regulator -- Do I need one? Some comments have suggested that brew pressure can be adjusted by varying a regulator on the input side of the pump (contradicted by the ProCon engineer). I'll be easily able to access the adjustment on the pump.

I don't have enough experience with these pumps to know for certain, but as indicated to you by Procon, the balanced bypass is supposed to be independent of inlet pressure. I'd still add a regulator for peace of mind.

(3) OPV -- I'm planning to install the Expobar's OPV, under the counter, in line fed from the output of the Procon, as a safety with the pressure set up above the brew range.

Most rotary pump machines have an OPV that is not used to regulate brew pressure (the pump is adjustable to set the pressure), but is set much higher (like 12 bar or so) for safety/expansion reasons. These typically dump to the drip tray. Where will you send the OPV outlet? Would it be easier to leave it in the machine and crank the setting up?

(4) check valve -- Someone recommended having one, in the machine I think, to prevent draining water if the machine is disconnected. Is there any other reason?

Plumbing code may require it. Cheap peace of mind, John Guest makes one for about $12 that you can add to the supply line.

(5) I plan to use John Guest 1/4" tubing from pump to machine, except for a short braided hose above the counter. Any reason to use anything else? How about JG quick-connects? Are they OK for brew pressures?

No problem. JG fittings aren't cheap but they are easy and flexible.

(6) Is there any problem or consequence to having the Hx pressurized during idle times? I just installed a brew pressure gauge, and I find that if I don't release it, the brew pressure stays in the thermosyphon circuit for quite some time. Presumably, the house line pressure would be there all the time if no solenoid is fitted, or if it stays on when the machine is powered up. I don't understand boiler dynamics enough to have a sense if this would affect thermosyphon action or whatever.

Line pressure would be there with no solenoid in the brew circuit. You can relieve the brew pressure by lifting the lever halfway if you had a solenoid.

Since you are plumbing it in, have you considered any water filtering/softening/regulator packages?

I have a much more basic question, one I was going to ask yesterday but decided to hold my tongue

Why bother? There is absolutely ZERO evidence that converting a machine from a vibe pump to a rotary will produce better shots; in fact, there is abundant evidence that rotary pumps produce no better shots than vibe pumps. Having participated in several randomized blind tasting trials in which a rotary pumped machine did no better than a vibe machine, I think I have a little bit of experience with this, in addition to actually owning the machines in question and using them on a regular basis.

If noise reduction is your aim, Dan Kehn, proprietor of this website, has written about "outboarding" a vibe pump, an exercise he has done that got rid of the noise factor, since most of the noise from a vibe pumped machine is the vibration of the rest of the machine by the pump, not from the pump itself.

Since you seem set on outboarding your pump in any event, why not just remove the pump that is in your machine and relocate it below the counter? You could do a simple relocation with a water reservoir somewhere and eliminate all the complex hoohaw stuff you are thinking about doing, and get basically all the benefits that I think you could reasonably seek. Alternatively, you could rig up an input solenoid with mains pressure if you want to plumb it in, but retain the vibe pump.

I can't come up with a single good reason to convert a vibe machine to a rotary, other than having a lot of money one wants to needlessly part with, or not having had one's quota of espresso machine aggravation this year.

ken

Thanks Jeff,

jesawdy wrote:Dick, here's a link at Procon that explains all those characters in the part number, Procon Standard Series Model Number Matrix.

Can you adjust the pressure or is it preset on that particular pump you have there? Can you post a picture? I am just curious.

FWIW, I just pulled a rotary pump (different manufacturer) rated at 600 LITERS per hour (~160gph), so I guess that can vary a good bit! This one also has the balanced bypass like yours.

The picture of the Series 2 pump on the Procon site is a good picture of the pump I have. I took off the acorn nut next to the inlet port, and the adjustment screw underneath is easy to adjust. Looking through the port, you can see that the adjustment screw simply adjusts pressure on a spring -- presumably controlling the output pressure. The acorn nut both covers the adjustment screw and locks it.

jesawdy wrote:Well, you'll need a relay to turn on the pump, might be a good idea to open a solenoid as well at the same time if one does not already exist in your brew circuit. A normally closed valve may help you sleep better. That said, it should not be needed. But, if you want to mess with mains pressure preinfusion, leave it out (but add the regulator). See Is there a purpose for the E61 middle brew lever position? for details.

That's a good thread on pre-infusion and E61. So: various comments suggest several results from and approaches to pre-infusion. (1) E61 does it. (2) Rotary conversion finally got good shot because of faster pressure ramp-up (Starbucks coffee). (3) Rotary conversion made machine less forgiving, tamed by needle valve after pump to control ramp-up. (4) Use partial lever lift or power switch to delay pump start and preinfuse with line pressure. (5) Add regulator to refine control with previous. I guess these latter two go with the general ethos of Hx-E61 brewing, where the operator gets to "control" a lot but may have difficulty figuring out what has what effect, exactly.

jesawdy wrote:Most rotary pump machines have an OPV that is not used to regulate brew pressure (the pump is adjustable to set the pressure), but is set much higher (like 12 bar or so) for safety/expansion reasons. These typically dump to the drip tray. Where will you send the OPV outlet? Would it be easier to leave it in the machine and crank the setting up?

I currently have the OPV drain(s) plumbed to my sink drain. If the OPV goes under the counter, the plumbing is just shorter. I'm sort of trying to take everything possible out of the machine, as part of another project (new case).

jesawdy wrote:Since you are plumbing it in, have you considered any water filtering/softening/regulator packages?

Yes, already done -- full Chris Coffee dual filter kit. I also have the ?-to-25psi regulator, but would think about getting one that would adjust up to 45+psi to be able to experiment up to my full line pressure. Or just leave it out and see if I later think I might want it.

I'll be happy to post pictures of anything that seems worthy (but I need to learn how). I'm currently experimenting with vibration isolation for the pump motor, which hums a bit. If I come up with anything, it might be a picture candidate.

Thanks,

Thanks Ken, all good questions (see below).

Ken Fox wrote:I have a much more basic question, one I was going to ask yesterday but decided to hold my tongue :P

Why bother? There is absolutely ZERO evidence that converting a machine from a vibe pump to a rotary will produce better shots; in fact, there is abundant evidence that rotary pumps produce no better shots than vibe pumps. Having participated in several randomized blind tasting trials in which a rotary pumped machine did no better than a vibe machine, I think I have a little bit of experience with this, in addition to actually owning the machines in question and using them on a regular basis.

If noise reduction is your aim, Dan Kehn, proprietor of this website, has written about "outboarding" a vibe pump, an exercise he has done that got rid of the noise factor, since most of the noise from a vibe pumped machine is the vibration of the rest of the machine by the pump, not from the pump itself.

Since you seem set on outboarding your pump in any event, why not just remove the pump that is in your machine and relocate it below the counter? You could do a simple relocation with a water reservoir somewhere and eliminate all the complex hoohaw stuff you are thinking about doing, and get basically all the benefits that I think you could reasonably seek. Alternatively, you could rig up an input solenoid with mains pressure if you want to plumb it in, but retain the vibe pump.

Well, there is "anecdotal evidence" (yes, an oxymoron). But no, I don't expect provably better shots. In this connection, the best I hope for is something like "a better overall experience." Mostly, this result will come from less/nicer sounds. Some from a knowledge of smoothly functioning mechanisms that I know well from having installed them. Any apparent improvement in taste, crema, etc. I promise to skeptically regard as part of the usual "believing is seeing" phenomenon.
I did start by considering an outboarding of the existing pump (see earlier thread). I was thinking about a bypass loop with checkvalves and so on to allow line-pressure pre-infusion and boiler fill. Finally, I decided a rotary would be simpler and probably more satisfying. (After all, it seems to me, one could make a pretty good case that the whole espresso thing is ultimately about satisfaction in one sense or another.)

Ken Fox wrote:I can't come up with a single good reason to convert a vibe machine to a rotary, other than having a lot of money one wants to needlessly part with, or not having had one's quota of espresso machine aggravation this year.
ken

Well really, compared to, say, finding a cure for cancer or similar high-value endeavor, is there any possible good reason for doing anything with coffee whatsoever? But if we agree that, however we personally justify it, spending hundreds of dollars and unremunerated hours on espresso is worth it, then I can be OK with the cost of my rotary pump. As to aggravation quota, my motto is: if it's worth doing, it's worth overdoing. All of us perfectionists spend a lifetime being limited, but in this case, my personal limit is somewhere the other side of a rotary pump. Besides, it's a nice piece of mechanism. Please excuse the lecture/rant.
And btw, I much appreciate your reports of well thought out and controlled testing/tasting. I've learned a lot from them. And of course, I very much appreciate the evident application of a high level of care and perfectionism therein. :-)

I have to agree with Dick on reasons for considering a conversion to a rotary. I too have been toying with the idea of converting my Brewtus to a rotary. My reasons are not for better shots. To me there is the conveniece factor of not having to refill the reservoir (it usually always seems to run dry in the middle of a shot when you are in a hurry), plus the noise reduction. I wasnt going to plumb the drip tray as the one on the Brewtus is fairly large. My only problem is convincing my wife to let me drill a hole through the granite bench top for the water line. She isnt so keen on the hole and thinks I will crack the bench top or something.

I enjoy tinkering with things generally so combining my tinkering with coffee is also a plus for me. At the end of the day pulling a shot knowing that i installed the rotary pump etc. would be quite satisfying and would add to my coffee experience.

I have an old Microcimbali lever machine from the early 80s that i restored and use occassionally on the weekends. I get a better shot from my Brewtus but using the lever machine is something a little different and again knowing I took the machine from non-runner up to current condition still brings a smile to my face.

so are the small pluses worth the expense? I guess it is all relative. For me yes, for others perhaps not.


here is a link on a rotary conversion for the minore that may be of interest.

http://ministrygrounds.net.au/blog/136/ ... conversion





Clint

jesawdy wrote:FWIW, I just pulled a rotary pump (different manufacturer) rated at 600 LITERS per hour (~160gph), so I guess that can vary a good bit! This one also has the balanced bypass like yours.

I got to thinking about this late last night. The pump in question that I quoted above is made by NUERT ( http://www.nuert.it ) and is model number APR06BZ, which translates to an NSF approved, BRASS PUMP, 600 L/H, RING COUPLING, BALANCED BY-PASS,WITH FILTER. Or at least that is what I thought.

The 06 may actually mean 60 liters per hour and not 600 liters per hour as I originally thought, although they do not list any such specified pump (link).

Anyhow, here's another rotary pump from another single group. Fluid-O-Tech ( http://www.fluid-o-tech.com/ or http://www.fluidotech.it/ ; 2nd site NOT Firefox friendly), RotoFlow, model PO1504 (balanced bypass, brass, clamp mount, no filter) which is rated for approximately 225 liters per hour (60gph) at 9 bar, with a 1725 (60Hz) rpm motor... see here for pump performance charts under various conditions.

erics wrote:Hi Dick -

I don't agree with what the Procon engineer told you as regards flowrate. This pump is pumping 21 times the typical espresso flow and me thinks that is putting the relief/regulating valve and the pump into uncharted territory. You might find it necessary to install a permanent bypass from the pump discharge back to the inlet and regulate this flow with a, say, 1/4" ball valve.

It would be interesting to know exactly what pumps EPNW sells for espresso machine duty as even the smallest Procon pump is five times the typical espresso flowrate.

Another point to consider is that you will be operating this pump at very near the rated horsepower of the motor and I believe the brew switch contacts may not enjoy that current for too long. Perhaps a motor relay would be prudent.

Should the Procon engineer still persist, it would be prudent to test the motor/pump and see what sort of pressure regulation you can attain. True, the pump won't heat up but that's because of the duty cycle you will impose. If you were operating this pump at a higher duty cycle, I would think the pump housing could get a little warm.

Hi Eric,

You're right about the motor load. I talked to the ProCon tech again (maybe not an engineer after all), and the lower volume pumps have different rotor, liner, and vanes. I didn't ask before about the motor power used, so he didn't consider that, and I guess he just wheeled out their stock recc for espresso usage. He said today that they always spec either 35 or 60 GPH for espresso usage. Perhaps with, say, a multigroup machine where you're flushing one while brewing on another, you need the larger flow rate. Looking at the ProCon specification chart, it certainly does look like a 15GPH would ask a lot less of the motor and do everything I need. I'll see how this one works and consider having it rebuilt to 15 if there's anything obnoxious about the way it works. I had planned a motor relay. As to "uncharted territory" for the pump and it's valve, it may be uncharted, but apparently, the pumps are widely used with these parameters. I've also read somewhere that pump makers think it wrong to use the pump valve to adjust/regulate brew pressure. Perhaps all this abuse of design spec's, if that's what it is, is just being covered up by the way-low duty cycles.

I've certainly found a variety of ideas about how these pumps work and should be hooked up. A prime example is that they're sensitive to input pressure; hence need a regulator. Perhaps some are. (Would they be less sensitive if over-spec'ed for flow?) You mentioned EPNW-- they have on the web about 5 different rotary pumps, three with standard clamp fittings, listed with flow capacities of 13, 25, and 53 GPH, but I didn't find any info about why to prefer one versus another, except maybe the dimensions. When I called them, they said the 1/4 horse motor was fine for any of them. Their ProCon is Model 112A060F11CB130, which is exactly what I have. Looks like about the same spec's as the RotoFlow that Jeff mentioned.

I hope to actually get it hooked up this week or next. I'll update with whatever I can observe.

clinto wrote:I enjoy tinkering with things generally so combining my tinkering with coffee is also a plus for me. At the end of the day pulling a shot knowing that i installed the rotary pump etc. would be quite satisfying and would add to my coffee experience.

I have an old Microcimbali lever machine from the early 80s that i restored and use occassionally on the weekends. I get a better shot from my Brewtus but using the lever machine is something a little different and again knowing I took the machine from non-runner up to current condition still brings a smile to my face.

so are the small pluses worth the expense? I guess it is all relative. For me yes, for others perhaps not.


here is a link on a rotary conversion for the minore that may be of interest.

http://ministrygrounds.net.au/blog/136/ ... conversion
Clint

Exactly my point, Clint. Some day I want to try a lever machine. I used a commercial one in 1959 when I worked at a "beatnic" coffee house in Detroit, but I can't remember much about it.

And thanks for the link. The motor in the pictures is identical to the one I got from EPNW. I can't tell what the pump is, but they all look similar.