Hey Nick,
Havent had any time to play with Arduino.
Im trying to get the first one rebuilt & sold to finance the work on the other one, which is getting the pieros, arduino, etc.....

Finally the uni semester is over, so Im finding some time to do some work on the machines.

I have been playing around with an idea of fitting a PT1000 RTD into each group head to measure water temp. This is largely dependent on the theory that the temp of the saturated group head is the same as the water flowing through the copper tubing and down onto the dispersion screen.
So I am hunting around for a pipe plug probe able to withstand the 135 psi present in the group head.

I think I have the interface worked out, a slightly modified wheatstone bridge to keep the range of interest narrow (85C to 95C) feeding a rail to rail CMOS opamp, which will output to an Arduino.

This is largely dependent on the theory that the temp of the saturated group head is the same as the water flowing through the copper tubing and down onto the dispersion screen.

I don't think this is the case.

I put a thermocouple probe into the waterstream within the banjo bolt, which gave very good results. I datalogged the banjo probe against a Scace, and the graphs essentially matched. Both my 2-grp and 4-grp were equipped with brew temp probes. After playing with them for a couple of years, I went back to just brewing espresso and enjoying it.

Hi Ross,

If you've fitted Piero caps then surely the brew water path is up the gooseneck, into the 3 way valve, and down to the dispersion block?

Rosscopico0 wrote:Here is the video so far, did most of the new togethewiring loom last night, waiting on more silicone insulated wire to arrive.

From whence did you source your silicone wire?

Hi Nick, the Pieros are going on the other machine (the one Im keeping), this one is still an AV.

Barry, I got the silicone wire from http://www.testpath.com
Where did you drill into the banjo bolt for the thermocouple?

For the pieros, I want to drill in and attach a pressure sensor (via some copper tubing), wondering if its possible to get a RTD in there too.....

banjo bolt probes were installed in hole drilled axially in the banjo bolt (flipped it upside down and drilled through the existing hole). probe passed through group lid (that's the tricky part).

Thanks Barry!

So the first machine is completed and being tested. It was doing quite well until yesterday afternoon, the left group started making a screeching noise. It was tools down time, so I left it until today.

Now both groups are making this sound, it seems to be coming from within

They are flowing well, so it makes me doubt there is an obstruction. To be sure, I took out the 0.6mm gicleur and the sound continued. I also took out the flowmeter impeller, in case it was somehow getting stuck, still no joy.

Has anyone encountered this before?

well, I put an external pump on my marzocco. It makes a big difference. Just my 2c

Ummmmmm, La Marzocco's all have external pumps (except for the new Strada)..........