Think of this as a mod idea for a poor-man's Speedster*. I wanna apply this idea to my machine if it really is within my modding capabilities; but thought I should ask here 1st for tips and wisdom.

On my machine, when I press the brew button, two things happen: 1. the group solenoid opens (so water would pass to the coffee); and 2. the rotary is engaged. I know if I could delay (2) for a few seconds (manually, using a switch), I would get line pressure (1.5-2bar) pre-infusion.

To me, it all sounds simple. I assume my pump gets power thru two wires, if I install a switch on these wires, I could control the pump's on/off state. So, if wanted the normal behavior (no manual pre-infusion), I'd keep the switch on the ON state. But if I wanted to pre-infuse, I'd turn the switch to OFF, press BREW, wait a few seconds, then turn the switch to ON and the pump would engage.

I'm missing a few pieces of info: what's that big white thing on top of the pump's motor? would it get hurt by such a mod? do these pumps have electronics or is my assumption that they're simple electric devices powered by two wires correct?

* yeah, I know, the Speedster does more than just let the line-pressured water pass to the group, it actually has a pressured device to manage infusion pressure...but, hey, I said poor-man's!

I have done something very similar, except I installed a time-delay relay that engages the pump 5 seconds after the switch is pressed. My epoca was pretty unforgiving before I made this mod, and it has had a marked improvement on my extractions.

The pump is a simple piece of kit - put mains power through it and it runs, turn it off and it stops. That's what happens when you press the switch on the front of the machine at the moment, and it will do exactly the same if you make your mod.

the main thing to be aware of with this modification is that you are switching mains voltage, and making that new pump switch nice and safe should be the first thing on your mind. Nothing like a good 220V belt to wake you up in the morning, though. It might even save on coffee!

Thank you for chiming in, Darren...lots of good news in your post .

darrensandford wrote:I have done something very similar

Oh, Darren, details, pics, please...pretty please?

darrensandford wrote:Nothing like a good 220V belt to wake you up in the morning, though. It might even save on coffee!

ROTFL ... this home barista is volt-proof...even this didn't save on coffee......yet!

I got the idea for doing this from an existing post here on HB, but I can't remember where it was now.

I'll try and get some pictures this weekend, but (from what I can remember - I hope I have this right!), the switch on the front (no automatic dosing) switches both the solenoid and the pump. The pump wires were wired from Live -> Pump -> Switch -> Neutral (yeah, I know, the pump was held live, which scared me a bit when I realised, especially as it's an external rotary I switched to, and it sits on the floor ).

The timer relay has two terminals that start the timer (and switch the relay), and two terminals for the relay output. It is rated for 240V on both the input and the output circuits, so I can quite happily run this from the existing 240V connections for controlling the time and switching the relay.

I changed the pump from the above to Live -> Switch -> Relay Input -> Neutral. I then added in new cabling to go Live -> Relay Output -> Pump -> Neutral.

I tucked the relay out of the way in the corner of the case, just under the cup warmer tray. I stuffed loads of melamine foam to insulate all I could already, so the relay stays pretty cool.

The only problem I have is that for some reason, if I don't press the brew button for a while, the next time I do the pump will start immediately. I -think- that the little neon light in the switch is somehow allowing some kind of bleed, pre-charging the relay timer. I actually like the way this works, so I haven't bothered to fix it. I always flush before I brew, so it's never an issue.

darrensandford wrote:I got the idea for doing this from an existing post here on HB, but I can't remember where it was now.

Probably Ken's The Impact of Preinfusion on the Taste of Espresso Shots or one its offshoots. BTW, lest you think that I'm a walking search engine, I found this by searching 'preinfusion' in the unabridged FAQs and Favorites.

Thanks for the walkthrough, Darren, I wish I was more handy at this stuff. I'm not, so I'll eagerly wait for the pics cuz I really don't get it .

Instead of the pump, now I'm starting to like the idea of switching the solenoid manually with a bypass switch. In theory, if it could be done easily, I'd manually open the solenoid to preinfuse then after a few seconds I'd press the brew button for the pump to kick in. Sounds good to me; and the solenoid wires are much closer to the front panel

HB wrote:...lest you think that I'm a walking search engine...

even the mothership wasn't willing to spoonfeed me with this.

Hi Max,

see here:

http://www.home-barista.com/espre...os-cons-t7963.html

Regards,
dsc.

coffee.me wrote:Think of this as a mod idea for a poor-man's Speedster*. I wanna apply this idea to my machine if it really is within my modding capabilities; but thought I should ask here 1st for tips and wisdom.

You don't need a Speedster to get adjustable line pressure p/i, the Vivaldi S1V2 comes with it for less then 1/3 the price.

Guys, guys, guys....Max is a simple guy hoping to do a simple mod and looking for simple instructions

Going ahead with the manual solenoid idea, let's have a look at the brew switch wires:


They are:

• 2x black, one coming thru the sleeve and another hooked to the white plastic connector(the connector is connected to nothing, BTW). What could this be? EDIT*: this could be unused power?
• 1x reddish, what's that? EDIT*:ground? i donno?
• 2x blue and 2x brown, should I assume:
  1 brown + 1 blue = power to pump and 1 brown + 1 blue = power to solenoid?

I'm hoping that by somehow installing a bypass switch(with your help!) using these wires, I'll be able to open the solenoid on demand without engaging the pump. I have a multimeter, if that helps!

* EDIT: I looked around the machine and it looks like ground wires are colored with light green/yellow strips. Black wires, it seems, are used for power, but can't confirm. The boiler element uses 1 brown + 1 blue.

I still haven't had a chance to open my machine up, but I think what I did was trace each wire from the switch back to it's source to get an idea of what did what. Also, pulling that rubber boot off of the back of the switch connectors will let you see which of those wires headed into the switch are actually wired together onto the same terminal. If it's the same as my Epoca, they will end in spade terminals pushed into the back of the switch.