blondica73 wrote:I have another Linea Mini question. I'm trying to figure out how to enable the water to run through the brew head at line pressure without enabling the pump, in essence, extending the preinfusion. Is the pump enabled by any of the 5V signals on the control board I could tee into?

I don't know the specifics of the LMLM, but this is a HUGE capability that I made sure I have when I modded my machine. It is certain that there are several approaches you can take to obtain this capability, some will be easier and possibly less cosmetically appealing, while getting it all "hidden behind the paddle", might be a bit more of a challenge.

Going from memory, didn't you disconnect the onboard pump and motor and remote mount a new one when you plumbed? That's what I did and it makes separate pump and solenoid control very much easier.

If you did this ^^^ you are already partway there.

-Peter

Perfect. So follow (some of this is long and irrelevant to you but it's partly a thought exercise):
If you were to take the power leads off the motor and then try to use the machine as always, you would get only solenoid operation and no pumping. If you went to the hardware store and bought an appliance cord with a plug on one end and bare leads on the other, (Big Orange actually sells these), and put those leads on the motor under your sink and plugged it in to a separate outlet from your machine power, the motor would start running. If you then spliced in an on/off switch into that line, your pump would now run at will according to your pleasure. Crude, but this would give you the control you want. Of course you would still have to face boiler fills and such (my machine has its own dedicated boiler fill pump ), so this as described would not be feasible for you.

BUT (going back to your existing setup)

If you were to splice an ON/OFF switch inline with your remoted pump leads, and leave it "ON", your machine would work exact as it does now. If during a shot, you flipped it to "OFF", your pump would stop while the solenoid remains open. It will be eerie... you will hear the solenoid buzzing. So here's what you can do: all the time except when you are ready to pull, leave it ON. When you are ready to pull, switch it OFF and swipe the paddle same as always. The solenoid will energize and line pressure will reach the puck. If one day you put in a Jake valve, you will be able to control the flow of your line pressure. When you're ready to hit the puck with the pump, flip your "interrupt switch" back to ON. At your pleasure you can switch the pump back OFF, for the final third, Slayer style. Or again, if you have a Jake valve, you can leave the pump running and slow the finish by closing the valve. Then terminate the whole shot by closing the paddle. Don't forget to leave the interrupt switch ON while the machine idles, so the fill calls will be enabled.

-Peter

Sounds like you are in line to be the pioneer of the LMLM community in this on the fly flow control space. Pretty excited to see how it comes out. I know people who are otherwise not considering the LMLM (or sold their LMLM to get a machine with flow control), who will be very interested pending your results here. Do keep us informed.

In the meantime, if you can splice in a pump interrupt (just a simple inline switch), you can begin "two speed" profiling, where one is line pressure, and the other is pump pressure. Or for simplicity, "low", and "high". This in itself is a crude variation of how Slayer (and the stock BDB) behave, where the classic "Slayer shot" would start in "low", go to "high", and finish the final third in "low" again. Rule of thirds, which has a whole thread here on HB.

-Peter