Do most plumb-in machines require external pressure? - Page 2

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cannonfodder
Team HB

#11: Post by cannonfodder »

Good to know. I was debating on jug feeding my machine after I finish the rebuild or plumb it in. Plumbing is relatively easy when you have your own home, much more difficult with an apartment or dorm.

100mph, that is third gear on my bike (I have 6 gears), I drive too fast to worry about my cholesterol.
Dave Stephens

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barry

#12: Post by barry »

RapidCoffee wrote:If you are near a water line, even something as simple as an icemaker kit from a local hardware store will work
it's not advised. the water line is too small to adequately feed the pump.

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barry

#13: Post by barry »

chris wrote:Without a constant line pressure your pumps output pressure will not be constant either.
zero input pressure seems pretty constant to me... better than unregulated line pressure in that regard.

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RapidCoffee
Team HB

#14: Post by RapidCoffee »

barry wrote:it's not advised. the water line is too small to adequately feed the pump.
Agreed. 3/8" would be better, but 1/4" works fine with some pumps (my Oscar came with 1/4" tubing). The flow rate capacity of 1/4" tubing should easily exceed the pump rate through the brew group. But it's probably not as simple as that...

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barry

#15: Post by barry »

RapidCoffee wrote:The flow rate capacity of 1/4" tubing should easily exceed the pump rate through the brew group. But it's probably not as simple as that...
yes, but when the boiler fill kicks in, the pump may cavitate.

phreich

#16: Post by phreich »

NOTE: THIS POST HAS BEEN UPDATED TO ALSO INCLUDE INFO FROM PROCON PUMPS AS WELL AS THE INITIAL INFO FROM FLUID-O-TECH.

I talked to the Shawn, one of the technical support guys at the Fluid-o-tech US headquarters, and got some interesting information from him. In case you don't know, Fluid-o-tech is one of the major suppliers of rotary vane pumps for espresso machines, often under the trademark name of Rotoflow.

If you aren't sure what a rotary-vane pump is, it is the type of pump that is used in commercial-style (and some prosumer) espresso machines -- unlike the "vibratory" pumps used in most home-style pump espresso machines. Some compact commercial-style machines have the pump mounted inside the case, and other (especially multi-group) machines have it mounted separately under a counter. Many folks call these pumps "Procon" pumps -- but that's a misnomer -- Procon is another manufacturer of rotary-vane pumps. It's like calling a facial tissue a "Kleenex".

His full name is Shawn Thompson, and he can be reached by email or phone (I'll post the contact information at the end of this post).

I asked Shawn some questions and got some surprising answers. Note that Shawn can only speak to the rotary-vane pumps built by his company. If you have a pump manufactured by another company you would need to check with that manufacturer to verify whether this information applies to their pumps. When I get a chance, I will call the Procon company and ask the same questions and will update the post with their answers.

UPDATE: I called the technical support line at Procon Pumps, and talked to Eric Taylor, their lead tech support person. I have updated the questions below with his answers (they are basically the same as Shawn's, with the exception that the Procon pumps can handle up to 6 ft (2 meters) of lift vs. Fluid-o-tech's 3 ft (1 meter) of lift. To help separate their answers, I will italicize the responses from Eric at Procon Pumps

Here are my questions and here's what he told me (and some thoughts of my own based on his answers).:

1. Shawn, can your rotary vane pumps draw from a non pressurized source (like a jug of water, or a 5 gallon pail)? His answer was, surprisingly, yes. Eric at Procon also said the same thing -- no problem drawing from a non-pressurized source.

I mentioned that this seems to be counter to what many have said in the forums and he said that this is an area of common confusion because people don't realize that the same pumps (in my case their "PO" line of rotary vane pumps) are used for many applications besides espresso machines, and they are capable of lifting water about 3 feet (or 1 meter) up from a non-pressurized water source. He cautioned that the supply for non pressurized water sources should be no less than 3/8" so as to not restrict the flow, and to minimize the number of fittings used for the same reason. He said that using a pump in this way would not reduce it's life appreciably. He did caution to make sure to listen to the pump, and if you hear a "buzzing" sound coming from it (caused by cavitation due to flow restriction) that you should figure out why your flow is restricted and correct the cause -- cavitation WILL cause shortened pump life.

Eric at Procon basically confirmed the same thing as Shawn -- except that he said their pumps have a maximum lift of 6 feet (2 meters). The same line size and minimizing restrictions also applies as does the warning about cavitation.

My thought is that it would be best to minimize any lift the pump has to do if at all possible, and if you have to do lifting, that you might consider installing a check-valve in the supply line -- just make sure it isn't one that restricts flow -- some check valves have internal springs that have to be overcome and this type would restrict flow. Other check valves are simple flaps or small ball bearings that close due to gravity and are easily overcome by a pump and would not restrict flow as much. You should be able to look at the specs of the check valve and determine what the flow restriction is for the given check valve. Another way to check is to just try blowing through it -- if you can easily blow through it in the direction of flow, then there won't be much restriction.

2. I asked Shawn if there was any problem drawing diluted citric acid based descalers through the pump and he said; "no, dilute citric acid descalers won't cause any problems". Eric at Proconn said the same thing -- he just said it should be flushed out of the pump after the descaling is completed -- it won't void their warranty.

This is good news for those of us lucky enough to be able to have plumbed-in machines -- we can simply draw the mixed citric acid solution in through the input line and descale the entire water path -- rather than having to drain the boiler and fill the boiler up by removing the safety valve at the top and filling it from there. Of course those using "pour-in" machines would simply pour the mixed solution into the water receptacle.

3. I asked Shawn whether it is necessary to put a pressure regulator before the pump when connecting to a pressurized water supply. He gave me some interesting information.

The short answer is; "no, there isn't any problem, as long as the line pressure is less than the desired pump output pressure". He went on to explain that the higher the input line pressure, the less work the pump has to do, and so higher pressure might actually make the pump last longer. He did caution that the input pressure needs to be lower than the output pressure.

Eric at Procon confirmed their pumps don't need input line regulation either, as long as the input pressure is less than the desired output pressure.

Shawn is not an "espresso machine guy" (he said he does enjoy espresso though), so my thinking is that you need to take into account the rest of the espresso machine and make sure it can handle a high line pressure. My further thinking on this is that commercial-style rotary vane pump espresso machines are plumbed to withstand boiler pressure at about 1 bar, and grouphead pressures at 9 bar (130 PSI), so I don't think this is much of an issue. All the solenoids are after the pump so they are built to withstand the higher pressure produced by the pump.

3. I asked Shawn about the two kinds of output pressure regulation devices used on these pumps (they are actually called adjustable bypass valves), and he confirmed there were two kinds -- one of which is a bit simpler and is more susceptible to changes in input line pressure (standard), and the other which has some "extra bits" in it and is not as susceptible to line pressure changes (balanced). He confirmed that their pumps can be upgraded pretty easily to the better bypass valve (and not too expensively).

Eric said that Procon also has the same two kinds of pressure regulation "bypass valves", and that pumps with a "standard" bypass setup can be converted to a "balanced" bypass setup that is less susceptible to input line pressure variances. He said that the suffix "C" on their pump model number indicates that the pump has a "balanced" bypass valve. Most of their pumps are ordered with the "standard" setup for some reason. However, unlike Fluid-o-tech, they don't sell the small parts direct to end users -- you'll have to contact one of their distributors to get the parts. Eric did say that they do sell "rebuild kits" for their pumps (cost about $80) that include the bypass valves -- so if you are rebuilding your own pump -- just order the rebuild kit for the "balanced" version of the series pump you have and you'll upgrade your bypass valve.

What this means to me is that, for a plumbed-in application, if I don't want to install a supply-side pressure regulator, I can instead upgrade the bypass valve to the style that produces a more consistent output pressure regardless of the input pressure. The reason I don't want to install a supply-side pressure regulator is to avoid the consequent flow restriction that occurs when they are installed, and of course the extra cost. It also should, according to the information he gave in answer #2, make the pump work less hard. If you are wondering what kind of bypass valve you have, you can look at your model number, and look at the following brochure and see if your pump has a "std" or "bal" in the bypass valve column. If it has "bal" than it is the better "balanced" bypass valve. Here's the URL:
http://fluidotech.mitric.net/Contents/D ... 9%20Ed.pdf

Here's a link to a brochure that specifies, for Procon pumps, which models have which bypass valve setup: http://www.edcodistributing.com/pdf/mat ... es2016.pdf

4. Shawn also confirmed that Fluid-o-tech does rebuild their pumps for about 1/2 of what a new one costs. For example, he said that the price to rebuild my 1979 vintage PO201 pump would be about $35, and would include all new wearing parts, bearings, and seals and would include a guarantee. Shawn also said they do sell new pumps direct to the public.

Eric mentioned that Procon no longer offers rebuild services for their pumps (this ended when they moved their manufacturing plant from Tennessee to Mexico), and instead sends their customers to one of their main distributors that was trained to do the rebuilding by them. Here's the contact info for that distributor: EDCO in Sacremento, CA, phn nbr 800-559-0415. http://www.edcodistributing.com.

Pretty interesting stuff, huh?

I hope this was helpful to some folks,

Philip
=========================
Here's the contact information for Fluid-o-tech I promised:

161 Atwater St
Plantsville, CT 06479
Phone 860-276-9270
Fax 860-620-0193

Shawn Thompson
Pump Analysis and Sales
shawn@fluid-o-tech.com

Here's the contact information for Procon Pumps:
Eric Taylor, Technical Support
etaylor@proconpump.com
615-355-8000

PROCON Products
869 Seven Oaks Blvd.
Suite 120
Smyrna, TN 37167

bernie

#17: Post by bernie »

phreich wrote:I talked to the Shawn, one of the technical support guys at the Fluid-o-tech US headquarters, and got some interesting information from him. In case you don't know, Fluid-o-tech is one of the major suppliers of rotary vane pumps for espresso machines, often under the trademark name of Rotoflow.

(snip)
Pretty interesting stuff, huh?

I hope this was helpful to some folks,

Philip
=========================
Here's the contact information for Fluid-o-tech I promised:

161 Atwater St
Plantsville, CT 06479
Phone 860-276-9270
Fax 860-620-0193

Shawn Thompson
Pump Analysis and Sales
shawn@fluid-o-tech.com
Interesting and very helpful. Thanks for taking the time to contact the source and then to post the information. I have 3 machines set up for remote operations and have never had problems running off a jug of water as long as I'm driving it with a flo-jet before it hits the machine pump. I hope your post hits a good archive for future reference.

Bernie

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Sponsored by ECM Manufacture
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cannonfodder
Team HB

#18: Post by cannonfodder »

phreich wrote: 3. I asked Shawn whether it is necessary to put a pressure regulator before the pump when connecting to a pressurized water supply. He gave me some interesting information.

The short answer is; "no, there isn't any problem, as long as the line pressure is less than the desired pump output pressure". He went on to explain that the higher the input line pressure, the less work the pump has to do, and so higher pressure might actually make the pump last longer. He did caution that the input pressure needs to be lower than the output pressure.
The issue is not the line pressure on the pump, but the line pressure on the internal solenoids/seals of the machine. All the rotary commercial machines I have used/looked at have a 4 bar max input. If your house water pressure is only 3 bar, there is no need for a regulator/reducer. But 3 bar mains is 43psi, which is pretty wimpy water pressure. Higher mains may make the pump last longer at the expense of the machine it is installed in. A pump is much less expensive to replace than the machine it services.
Dave Stephens

phreich

#19: Post by phreich » replying to cannonfodder »

Dave, thanks for your response -- it got me thinking but I'm not sure I understand the reasons for the concern....

The 3way solenoid/valve has to handle 9 bar brew pressure. The solenoid that diverts the water from the pump to either the boiler or the heat exchanger also has to handle up to 9 bar pressure. I don't think there are any other solenoids in most of these machines.

The boiler, steam and hot water plumbing seals and valves only have to handle up to 1.5 or 2 bar of pressure because the pressure the safety valve on the boiler only allows typically about 1.5 to 2 bar pressure, and the pressurestat or PID is usually set to allow only about 1 bar normal operating pressure.

However, all the seals and plumbing for the heat exchanger and grouphead have to handle the 9 bar of pressure (about 130 psi) required for brewing.

However, maybe i am missing something? I look forward to further thoughts.

Philip

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stefano65
Sponsor

#20: Post by stefano65 »

try and see if your non plumbed in pump will reach 9 bar
you will not go any higher then 6-7 at the most
Stefano Cremonesi
Stefano's Espresso Care
Repairs & sales from Oregon.