cannonfodder wrote:You could also put an adjustable delay on make relay on the pump. That is what I did on my big two group. You raise the lever to the brew position, mains pressure preinfuses the puck then after X seconds the pump kicks on. Now for the caveat. The lever actuated E61 brew group has built in preinfusion. Once the pump is activated, it takes 5-7 seconds for the pump to fill the expansion chamber in the group. During that time, the puck is slowly infused from mains pressure to pump pressure. If you have an auto E61 group (the solenoid activated version) that process takes much less time, as do rotary pumps. In those instances you may get a larger impact with preinfusion.

This sounds interesting and has the nice side effect of not modifying internal group parts. Do you have a schematic of your electronics package you care to share? I could Google it but if you already have a working model, I'd like to copy it. Thanks!

That machine is long gone but it was a simple hookup. Power to the relay, snip the hot line going to the pump and put it on the NO side of the relay.

It occurred to me that a timer would mean waiting *every* time I lift the brew lever. Want to clean off that shower screen? Wait a few seconds. Want to backflush? Wait a few seconds. Sigh... So, back at the drawing board. Anyone have some input on my original proposals?

Yours doesn't work like this:


I think it'd be hard to get the true middle to flow water... since it's the point where it probably has the least resistance (before pushing up on the upper pin) - so maybe those machines that flow in the middle have a tighter lever operation...
?

No, mine does not allow any water to flow in the middle lever position. I'm super jealous. Is yours the latest version of the Duetto II? Or, do you have the HX Duetto? It appears to be slightly narrower than my machine.

It's the original Duetto (DB not HX)

You said that if u lift a few more degrees it flows.... but when u let go it pops back to the middle?

Mine may have been like that in the beginning... I don't remember, but u can see it kinda sticks now in several middle spots. When I took off my mushroom recently for cleaning, I noticed some wear on the pin... so maybe has something to do with it.

Anyone have some input on my original proposals?

The cam itself appears to be very symmetrical about its axis of rotation and is silver-soldered to the shaft to form an assembled part. Even if it could be successfully de-soldered and repositioned, you would be effecting both "ends" of the operation: brew & exhaust. Therefore, NOT RECOMMENDED.

You dismiss Dave's application of the delay-on-make relay too quickly . This is, by far, the easiest and least complicated path to accomplish exactly what you want. And, to add to its "goodness", it is fully adjustable. I would not snip any wires but would rather make up a wire harness such that I could easily revert the machine back to its original physical configuration.

PS - the brew valve movement is 0.066" or, a little over 1/16" from closed to fully open on a new cam.

For Ben - you have some squeaky-squeakies there - time to disassemble (again, ) and apply a little Dow 111 to the wearing surfaces.

I must of read your mind Eric before I read your post I was just down there taking off the lever for first time...

Here's a pic... I cleaned it off and used some food safe high heat silicon:


It made it super smooth now... with just a flick it goes up to the middle and water flows - a small flick down and it stops.... much nicer.

Kinda poor pic of inside while I was there... may show why with smooth operation it's more likely to not engage the top piston:

aaespresso wrote:It occurred to me that a timer would mean waiting *every* time I lift the brew lever. Want to clean off that shower screen? Wait a few seconds. Want to backflush? Wait a few seconds. Sigh... So, back at the drawing board. Anyone have some input on my original proposals?

Use a switch to enable delay or not.

NOTE : check on the specifics, but you should be able to just short across the delay delay terminals for 0 delay

aaespresso wrote:It occurred to me that a timer would mean waiting *every* time I lift the brew lever. Want to clean off that shower screen? Wait a few seconds. Want to backflush? Wait a few seconds. Sigh... So, back at the drawing board. Anyone have some input on my original proposals?

That is why you use an adjustable timer. Change it to 0 for no preinfusion for cleaning or if you want to try the same coffee without the added infusion time.