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
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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.