Now that my Elektra is up and running, I've been thinking about this mod a bit more. My preliminary (VERY UNSAFE) idea was to toss in a switch in series with the pump power wire. The reason that this is unsafe, of course, is that I might forget to re-enable the pump switch. Then, when the brain calls for autofill, if line pressure is not sufficient to overcome boiler pressure, the boiler may drain or simply not fill, and the heating element may eventually burn out.

Disclaimer aside, I might still try this just to convince myself that a real preinfusion button is not needed (for the reasons that Phillip gave above). In theory, having a separate on/off switch for the pump would allow me to disable the pump, press the shot button to engage the group solenoid (for line pressure preinfusion), and then enable the pump to ramp up the pressure.

Hi Dan,

You might consider running a momentary switch to the group solenoid in PARALLEL with the existing switch circuit to the solenoid. That would allow you to close the solenoid by itself, thus allowing you to try pre-infusion to see if it makes a difference. You would hold the switch on, and then engage the brew switch when pre-infusion is complete so the group solenoid doesn't open up in between.

I am assuming that your brew switch is like mine -- a SPDT switch that has two four wires going to it -- controlling the pump and the solenoid as separate circuits. Basically, the switch is controlling two separate circuits simultaneously. You should see two wires coming to it from the switched side of the power switch (or they could be jumpered together on the switch), and then two "output" or switched wires -- one going to the group solenoid, and the other going to the pump or to a solenoid that activates the pump motor.

You would want to put the momentary switch in parallel with the group solenoid circuit. That means you would run a wire from the on-off switch, or the hot side of the brew switch to your momentary switch, and then run the other wire from the momentary switch to either the solenoid itself, or to the "output" or switched side of the brew switch. If it were me, I would just connect to the brew switch -- it would involve shorter wires and would be simpler to install. Either way, make sure you use at least the same size of wire as is currently being used (probably 16 or 18 gauge) to control the group solenoid.

As I mentioned in an earlier post -- I have decided NOT to do this mod to my Elektra because I found I agree with other Elektra owners -- it simply isn't needed because of the Elektra engineer's designed in 3-4 second pressure ramp-up time, and the extra dispersion block causing a more even soaking of the puck. The shots taste great as they are They are, IMO, much better than than I get at the local *$.

I hope this all makes sense to you -- its difficult to describe circuit mods using just English....

Good luck,

Philip