Spurred on by Ken F's and Jim S's exploits with Ken's La Cimbali Jr, I decided to install a timed relay to add preinfusion to my rotary pump Wega Lyra. See: http://www.home-barista.com/espresso-machines/impact-of-preinfusion-on-taste-of-espresso-shots-t1317.html

The Wega uses the "E60.5" group, which does not have a lever/cam and doesn't preinfuse. Ken's and Jim's posts suggested that preinfusion may be helpful with a rotary pump, and I thought it was worthy of a small experiment.

Ken generously emailed his description of the timed relay he's using as well as wiring instructions, which he got from Andy S. Andy's instructions to Ken read:

"Neutral wire is hooked to terminal A (on timed relay).

Hot side voltage that normally goes to pump goes instead to both B terminals (on timed relay).

After time delay period, terminal C (on timed relay) is energized. C is hooked to pump motor hot side. "

My difficulty is figuring out which is the hot, which is neutral.

The pump motor on my Wega has 5 wires going into it - Blue1, Blue2, Brown1, Brown2 and green/yellow. (Green/yellow appears to be ground - the ground connections to the Wega frame are all Green/yellow.)

Blue2 and Brown2 connect to the motor start capacitor, so they're out of the picture.

That means the relevant "hot" and "neutral" are Blue1 and Brown1 - but which is which?

The only hint I have is that Blue1 connects to terminal F5 labeled "POMPA" on the GICAR controller (see photo below).

On the other side of the GICAR, there's a diagram showing "+ OUT -", and there's one blue wire connected to the + side.

So I'm guessing blue is hot and the brown is neutral?

Any hints, including suggestions for how to test whether that's correct?

Thanks,

Rick

My advice is to buy a cheap voltmeter and check continuity against the plug. The wide terminal is neutral and should show continuity with the neutral wire no matter whether the pump is on or off. Your quite likely to be right about the hot wire being the one on the Gicar controller, since the neutral wire should never be interrupted in proper wiring.

another_jim wrote:My advice is to buy a cheap voltmeter and check continuity against the plug. The wide terminal is neutral and should show continuity with the neutral wire no matter whether the pump is on or off. Your quite likely to be right about the hot wire being the one on the Gicar controller, since the neutral wire should never be interrupted in proper wiring.

I second Jim's advice, BUT, it probably does not matter. I have found the electrical wiring of my Junior to be ultra tres confusing. I got variable results and even did such things as swapping the input wires as they come into the machine at the first terminal block, which in theory should switch the polarity of the machine (but it did NOT). There may be something in the way that these things are wired that switches polarity in a way that the user cannot control. In the end I just took what seemed to be the most "consistent" results and wired the timer that way.

The wiring that Andy suggests can't harm the machine, since the worst case scenario is that the switch does not activate and hence the pump does not turn on. You are in effect using the pump wiring to both power the onboard relay and to close the circuit when the timer kicks in. If you don't have a voltmeter (and I'd be SHOCKED, Rick, if that was the case), I think you can just wire it assuming that the brown is hot, which in theory it should be. I think it will work either way. The green/yellow wire, as you correctly surmise, is the ground. I should add that at various times, both Michael T. and Andy S. have suggested this circuit SHOULD work in either polarity. In my case it certainly has.

The next thing to do is to get a handle on what is your input water pressure, best done with a PF manometer, however since you have a rough idea of what it is anyway, you can test as we did to see if you get full preinfusion of the puck in around 6 seconds, at mains (not pump) pressure, and if so you can surmise you have somewhere's in the 3-4 bar mains pressure range.

Good luck and keep me posted on how this works out.

ken

Jim and Ken,

Thanks to both of you for your valuable tips. I do, indeed, have a multimeter, and will have time to check as suggested tomorrow. (Work interrupts many fine days, and today is another one of them.) A PF manometer is scheduled to arrive on Saturday, so I'll be able to check mains pressure Sunday. I found a local source for wire rated for 150 Celcius, and insulated quick connectors. There's even a threaded hole in the Wega frame where I can mount the relay up high, and away from the boiler, so that the timer can be easily adjusted simply by taking the cup tray off the top of the machine. I should be able to report back on results by Monday.

Cheers,

Rick

Andy's instructions to Ken leave me with one wire unconnected, and the pump doesn't come on.

Following the instructions literally, I have changed the setup from:

Original
Hot----------->pump
Neutral------>pump

To:

Modified
Hot------------->Time delay input B1 and time delay input B2
Neutral-------->Time delay input A

and

Time delay output C (delayed hot)--------->Pump

This leaves no neutral connected to the pump. Am I taking this too literally? Where does the neutral wire that is now left hanging out of the pump connect to?

Behaviour
When I turn on the pump switch, the solenoid opens and water flows through the grouphead under mains pressure. After a few seconds, the time delay relay clicks, but the pump does not come on.

??

Rick

Java Man wrote:no neutral connected to the pump

Yup, in addition to the neutral hooked up to the time delay relay, you still need a neutral wire connected to one terminal on the motor.

Thanks, Andy. Connected and working. Can't wait for it to warm up so I can find out whether there's any difference in extraction.

Cheers,

Rick

The time delay relay has been installed in series with the rotary pump in my Wega Lyra ("Mininova Inox" in Canada) for 5 days.

I won't attempt to conduct an objective evaluation of whether the resulting preinfusion makes a difference in shot quality. First, it would be difficult to be objective since IMHO, there's so much variability in dosing and tamping that these uncontrolled variables would render any comparison meaningless. To make comparison even more difficult, I just got a new grinder. The grinder with which I've spent the past 5 years has been cleaned up in preparation for sale, and I don't want to delay the sale by playing scientist. And the idea of conducting anything remotely like an objective comparison using the new grinder is laughable -- working with a new grinder is a little like learning to make espresso all over again.

I do have one noteworthy observation. The "preinfusion" relay has changed the machine's autofill behaviour. Since the boiler refills in less than 5 seconds under mains pressure alone, the pump doesn't activate in day-to-day autofills. This is a benefit that fully justifies the expense of the relay since my Wega made a gawdawful noise when autofilling. The harsh mechanical cacaphony of rotary pump activation and the autofill solenoid chattering filled our kitchen at the most unexpected times, often startling my wife and guests. I have endured numerous complaints about it from the B&C, but she has remarked at how much better it is since the time delay relay was installed.

Case closed, and thanks to all who provided advice and information.

Rick

Where did you get the timer?

As per Ken F's recommendation:

http://www.mcmaster.com/asp/enter.asp?partnum=77055K47

Rick