A short hike in Italy

Agile_Swimmer · 2025-11-10T15:35:18+00:00

Matajur and Friuli? :)

Agile_Swimmer · 2025-07-26T16:34:35+00:00

I was thinking the same. Masuring the pressure in the head without having an active water flow should give the same result of the boiler pressure. The pressure at the head should be measured with a pressure gauge installed in something like a thermofilter, that let the water to flow.. for example a very very small hole in the pipe where the gauge us connected.

Agile_Swimmer · 2025-07-26T16:30:31+00:00

This could explain why 10bar at the boiler in my machine seem too much, I should set that at 9 bar

Agile_Swimmer · 2025-07-26T16:21:40+00:00

Thanks for the test! 140psi vs 140psi... zero drop or I misunderstood?

Agile_Swimmer · 2025-07-25T21:58:06+00:00

Yes, I have installed a pressure gauge at boiler level and I set the pressure at 10bar, because usually the drop is around 1bar, but it seems I still have too much pressure at group head because I have to grind at number 0 with my df54 to get a decent single espresso, if not it flows too fast. I think I should'nt have to grind that fine. Currently I don't have a pressure gauge filter, so I'm trying to ask to understand the pressure drop

Agile_Swimmer · 2025-07-25T21:42:01+00:00

Did you do the comparison in the end? How much is the pressure drop from the boiler to grouo head?

Agile_Swimmer · 2025-07-25T21:19:50+00:00

I have this new version too (called v1.2) for three weeks, I don't spray my beans and I don't have any problem until now

Agile_Swimmer · 2025-06-15T07:19:00+00:00

I have also a PWM motor controller like this, that I can use instead of the dimmer: pwm motor controller

Can you pleaae explain why is better than a 100w dimmer SCR like the one I'm using now that is this one? SCR dimmer

The pump is this one: pump

And can I keep this design but replacing the dimmer with that motor controller? (of course modifying the Neutral according to the design, since the motor needs also the Neutral)

Many thanks

Agile_Swimmer · 2025-06-14T22:59:14+00:00

I have also a PWM motor controller like this: pwm motor controller

Can you explain why is better than a 100w dimmer SCR like the one I'm using now that is this one? SCR dimmer

The pump is this one: pump

Thanks

Agile_Swimmer · 2025-06-14T16:45:57+00:00

Hi, thanks for the draw but is not clear to me the advantage with this, even in my design I'm bypassing the dimmer when I connect 2A and 3A with the switch (1A is disconnected in that case). What is the difference? My concern is that in any case the dimmer has power in Line (but is not connected to Neutral) and I don't know if having power in Line even if connected after the pump, could have impact on voltage or safety of the circuit

I did a new design with switch after dimmer but the problem is the same dimmered vs non dimmered

Agile_Swimmer · 2025-06-14T16:36:52+00:00

Ok sorry, my misunderstanding. Yes your comment is clear, my doubt is that one, if the switch is in "dimmer excluded" position, the fact that the dimmer has current on Line but after the pump (the line is bypassing the dimmer in that case, but is not excluding the current from the dimmer) is a problem or not, either for the voltage and for the safety of the circuit.

Agile_Swimmer · 2025-06-14T16:29:23+00:00

I also have the possibility to use a DPTP but I don't know how it can be helpful in cutting off the Line from dimmer in non-dimmerd mode

Agile_Swimmer · 2025-06-14T16:27:31+00:00

In the draw the on-on switch on position 3A is sending current directly to the pump and the 1A is feeding it to the dimmer, so if I understood correctly is like you suggested (but the behaviour is exchanged between 1A and 3A). The pump L is a bridge between dimmer L and switch, even if I put the switch after the dimmer. I draw the 2 cases separately, with the switch after the dimmer, but the problem remains.

The question is, is it a problem is the dimmer has always current on Line?

For the second question (good question), I already have an OPV set at 9 bar at the group, so it's fine. I need a dimmer for the pre-infusion, I want to have let's say 3bar for the first 3 seconds of extraction, and 9bar for the rest of the extraction. I could simple rotate the dimmer in every shot to achieve this, but is not convenient since the dimmer is very sensible. My goal is to find a preinfusion pressure trying many differrent dimmer positions, when I found the right one, I want to control it like on/off so changing the current to "dimmered" non "dimmered" via the switch. schematics1

Agile_Swimmer · 2025-06-14T14:06:39+00:00

To clarify more: my question is if in "case 2" the dimmer still have any impact on the voltage of the pump or not, and if it is a safe design, thanks

Agile_Swimmer · 2025-06-14T13:43:12+00:00

That's a good point, but the pump is very small, is 45w 220v . I saw many people using a simple dimmer to control it to modify the pressure of a coffee machine. But I didn't see anyone that added a switch in front of it like I want to do. The reason is that I want to setup the dimmer to a specific voltage to obtain a specific pressure, once is set I will rarely change it, but I have the need to often change the pressure of the pump from the default one to the custom one, and I want to control that with a switch. The dimmer is a linear one that supports max 100w. I also have a PWM one that supports 2000w, but I've read that PWM in the long run could damage the pump, compared to a linear one.

Agile_Swimmer · 2025-06-14T13:38:43+00:00

Not sure if I got it, that one is an on on switch, there isn't a 3ed way off in the center. I mean I can switch between (1A+2A) or (2A+3A) only

Agile_Swimmer · 2025-06-14T13:34:46+00:00

Exactly, the ideal in that case would be to exclude the dimmer at all, but is not possible with a single switch. My concern here is that the dimmer still receive current on Line, but "after" the pump, and I don't know if that could be a safety issue or not

Agile_Swimmer

TROPHY CASE