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.

coffee.me wrote: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?

The big white thing is a start capacitor. If you trace those wires back, with the machine unplugged, you will find that only two enter the motor/capacitor assembly. One of those two, for most machines, will be electrically connected to one of the prongs on the power plug. That's your motor neutral lead, and the other is your motor hot lead. You'll want to have a cheap multimeter for all this. If you get a delay-on-make relay like the one mentioned in Ken's thread, it will have four or five terminals. Two are marked as power for the relay itself, one will be the common output terminal, and if there are four the last will connect to the common some period of time after the relay receives power. If there are five, one will connect to common when it's first energized (the "normally-closed" contact), and one after the time has elapsed (the "normally-open" contact and the one you want).

You'll need crimp-on spade connectors the size of the terminals on the relay, along with a crimping tool. You'll also need wire of the appropriate size, usually 16 or 18 gauge, with insulation rated for the temperature it will see inside the machine. A reasonable source is to go to an auto-supply store and ask for primary wire, since the under-hood temperatures are in the range you want. You should be able to get the connectors there as well; ask for a demo of the crimp tool if you've never used one. A properly crimped connection is more reliable than a soldered joint, because you're actually forming a gas-free cold weld.

The motor hot lead, i.e. the wire that used to go to the motor hot input terminal, needs to connect to one of the relay power terminals and the relay output common. The relay normally-open lead then connects to the hot input to the motor. The motor neutral should connect both to the neutral input to the motor, and to the other relay power terminal.

Once all this is done, check with the multimeter to verify that none of the leads you touched connect to the frame of the machine. Once you've triple-checked your work, plug the machine back in and power it up. Then time the activation time of the relay and adjust it; you'll need to mount the relay in such a way that you can safely get a small screwdriver in to adjust it, as well as so that it won't be sprayed in operation.

Hope this helps.

Best,
David

My preferred way is still controlling the solenoid manually as discussed above. Darren suggested pulling the rubber boot off of the back of the switch connectors for a better understanding of what they are; I'll hopefully get a chance to do that today. I'm also planning to try pulling out these colored connectors(one at a time) till I find which one(s) activate the solenoid.

DavidMLewis wrote:Hope this helps.
Best,
David

Thank you David for your detailed instructions. I'm sure that will be alot of help if I go with modding the pump with a relay.

Hey guys, who needs* a Speedster? My mod is done!

WIRES
=====
Turns out the 2 blues, 2 browns and 2 blacks are wired together (same colors) onto the same terminals; just as Darren hinted. Now, using very strict scientific methodology (i.e. pulling out wires then pressing the brew button ) I verified that blue & black runs the pump, brown & reddish runs the solenoid. Yahoooo!

MAGIC SWITCH
============
One old quirk of my brew button is that if I press on it lightly the pump runs without opening the solenoid. Yup, you guessed it! I swapped blue+black(pump) and brown+reddish(solenoid) so now when I press lightly I activate the solenoid for a few seconds then give the button a manly press to start the pump .

KISS
====
No new wires, switches, relays, nothing...mod done, max happy...hmmm, we'll see how it affects taste.

Thank you guys, especially Darren, for your replies.

* I do, I do, I soooo do

Glad I could help! I was just going to post to apologise for not posting pictures, as I am having a bit of camera trouble.

My switch actually does the same thing - a light press gave solenoid only, a harder press gives pump, but it was very hard to do consistently, and it depended on where I pressed the button, so I went for the timer just to make it a bit more controllable, and so I didn't have to stand there for 5 seconds with my finger on the pump when I could be brushing out the grinder or steaming some milk

So true, it's of course hard to be consistent...it's just a quick and dirty way of trying out preinfusion.

I've been preinfusing not based on time but sort of like what I'd do on the Caravel: preinfuse till the first, slightest, brown spot show on the bottom of the basket (naked PF), then hit full brew.

So far I've done a few doubles and a couple triples (planning to do singles today), and my first impression is a very good one. It seems the gentle wetting of the coffee bed eliminates all disturbances to it; very eager to try singles now as they are more sensitive to water flow rate.

I set up my old two group Faema with an adjustable delay on make relay. That way I could dial in the mains preinfusion time before the pump kicked in.

One more thing I forgot to add, I actually installed a separate switch for controlling the solenoid manually...it's been a few weeks now .

So, how does the pre-infusion affect the time of a pull? Is the pre-infusion in addition to the 25-30 sec one would expect a normal doppio to take before it starts to blond, or is the pre-infusion period included in that period?
Meaning, does the shot now blond at 25-30 seconds from the beginning of the pre-infusion still, or does it start to blond at 30-35 seconds from the beginning of the pre-infusion?

Chris, total time has increased from [shot time] to [preinfusion time + shot time].

When I was running a similar setup my shot time increased as well but it was not a total combination of both times. Since the puck was fully infused before the pump kicked in the extraction had already begun. I believe it added about half the time of the mains infusion time. So if the shot using a particular coffee was best at 28 seconds and I ran 8 seconds of infusion under mains my actual pump on time was something like 32 seconds not 36 seconds. Otherwise I would get some over extraction in the cup. But every machine/coffee/taste is different.