phreich wrote: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.

True, but only for ~30 seconds and a few drops of blowby is inconsequential at that time. According to the techs at Chris' Coffee, some espresso machine group solenoids will drip-drip-drip if subjected to more than 60 PSI for an extended period.

stefano65 wrote: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

I'm not sure what you mean by this. I run my machine off of a static 5 gal bottle, and my pressure can be adjusted anywhere from 0-15 bar. Espresso machine pumps generally have much more power than they need.

The difference would be applying "x" psi to the inlet of the pump and the inlets of the solenoid valves 24/7 or applying ~ 130.5 psi to some of these components on a much smaller time frame.

As regards the operation of a pump with either a standard bypass valve or a balanced bypass valve, there exists NO PUBLISHED data that I am aware of that displays the performance of a pump so equipped. For sure, both F-O-T in Italy and Procon have conducted tests and thus have this data - its just not available.

This is all good news, as I have been running my Vetrano off of a bottle, kept at machine level, for a couple of years. I haven't noticed any problem, and can easily reach the desired pressures.

Glad I found this post. This is the exact stage I'm at with my Linea 4av rebuild.
I would like to run it from a 5 gallon water jug, but still not sure how to go about it.
I have a 1/4hp motor and a Procon pump.

What kind of water lines or tubes do i need to get?

Here is my confusion as to which approach is best:

A. have the pump and motor on the floor next to the jug of water,place the tube in to the jug from the top making the pump pull water.

or is it best to have the jug above (maybe at the same level as the machine), while the pump and motor are on the floor.

or better suggestion?

Do I still need to get a check valve for either set up?

I'm not planning on keeping the machine, just want to have clean water run through it while testing it and maybe pulling a shot or two
Not interested in a flojet btw.

Also, both pump and motor are new so was wondering if i need to adjusting/calibrate anything on either one before their first use?

Cheers

I stand by my original post on page 1 of this thread:

HB wrote:Also see the thread Flojet and rotary pump questions. The Procon pump is spec'd at a six foot vertical lift, so presumably a check valve would suffice (to prevent the water from draining out and introducing air bubbles). That said, I would double-check with the vendor before buying because the manufacturer may call out positive pressure, as was the case for the Elektra A3.


Ball-type check valve assures water flows only one direction

My comments are consistent with Procon's recommendations on page 2 of this thread:

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

The check valve is there simply to prevent air from being reintroduced into the inlet tubing. It makes no difference whether the jug is below or above the espresso machine. As a noteworthy point of reference, the espresso machines at the SCAA barista competitions are run directly from 5 gallon jugs without positive pressure. That said, some espresso machines do rely on positive pressure to refill the steam boiler instead of using the rotary pump, some don't, and some are programmable (e.g., the La Marzocco Strada lets the operator pick whether the pump runs to refill the boiler). When in doubt, read the owner's manual.

coffeekam wrote:Also, both pump and motor are new so was wondering if i need to adjusting/calibrate anything on either one before their first use?

Yes, you'll need to adjust the pump to your desired brew pressure. Search the forums for instructions as required.

Dan,
thank for confirming all of the info.
Just help me with this and I think I should be ok after: what type of hose do I need from the jug to pump? and the one from pump to machine?
vinyl, SS mesh or rubber?
I'm a bit confused about the check-valve: does it go on the hose that's dipped into the jug, or on the hose that is going into the Linea?

The line on the outlet side of the pump to the espresso machine must be rated for +150 PSI since it will be subjected to full brew pressure; the stock one is flexible tubing wrapped in braided stainless steel. If you run from a bottle, the line on the inlet side is not subjected to pressure, so ordinary flexible tubing at your local plumbing supply will do (around here the plumbing code calls for tubing rated at 100 PSI @ 70°F, though typically the mains pressure is regulated down to 55-60 PSI on entry to the house). The check valve would go on the end of the input line in the bottle.

You also need a check valve on the discharge side of the pump if the Linea is not already equipped with same via its internal plumbing - who knows what the previous owner(s) have done? LM Part Number L032/P is appropriate.

The check valve that Dan referred to is termed a "foot valve" and should be designed for minimal resistance in the "correct" direction.

Have you been to the LM website? They do offer a somewhat reasonable installation guide. There is also substantial info here: http://www.home-barista.com/downloads/ .