Finally each group is similar to other groups, asbobbee schreef: za 02 mar 2019, 20:11 Zeker de BZ serie van bezzera vertoont grote gelijkenissen door de verwarmde groep.
1 - you can insert a portafilter
2 - you need any kind of heating
3 - the surface finish is chrom
4 - it is in any way round and installed on the front of a machine
Often people think that it is very similar to a BZ07/10 because we use heating cartridges.
But we decided after some measurements to not use the cartridges to heat the brewgoup for a long time. Brewgourps heated by cartridges and controlled by a thermostat is having always a remarkable hysteresis. It is something like 3C difference from the lowest to the highest temperatur within 2 or 3 minutes.
To avoid misunderstanding: this is ok and it is working.
But we decided to attached the brewgroup to the boiler by a 6mm copperbridge to get a more stable heating of the group.
We saw that cartridges are very good to have a fast startup: 20-25 minutes. And as we doing the programming of the arduino due by ourself we have been able to lower the time to ~12-13 minutes (with 2 x 100 Watt cartridges).
After the thermostat indicates that we have ~90° we continue heating by 90 seconds (what means: ~105 C). It is kind of overheating the group to support the heating of the other parts inside the machine.
As you see: we use known technology but we tried to improve the way of using it to get useful results. 12-13 minutes for a complete heating up a boiler-machine is very useful

I hope you understand what I try to say (with my English).
You can find some information also here: http://xenia.coffee/thermische-eignung/ if you the the translate-button the the bottom.