malling wrote:John saturated groups are not exactly the most commen group in Prosumer machines.

these days you find Them in LM, KvdW machines etc. And they still need a 2-3oz cleaning flush.

I never said they were common did I? I've done plenty of testing with a Scace/Fluke 54 & have my offset adjusted so that no flush is necessary to hit my set brew temp. The cleaning flush is done after I pull a shot & first thing in the morning.

JohnB. wrote:I've done plenty of testing with a Scace/Fluke 54 & have my offset adjusted so that no flush is necessary to hit my set brew temp. The cleaning flush is done after I pull a shot & first thing in the morning.

I'm not arguing, just trying to understand. I have my offset set properly too (at least I think I do). According to BillC, my displayed temp should equal the temp measured by the Scace/Fluke once the temp has stopped rising. Once I set that, I experimented with differing flushes, starting with none. I found that a 6 second flush put my Scace/Fluke measurement within a degree of target and rising during the shot to the target temp within 5-6 seconds. Maybe that's a function of my Linea?

aindfan wrote:I think there was a thread titled "one and a half boiler HX" but I'm having trouble finding it... please post a link if you know what I'm talking about!

HX Heaven or 1½ Boiler

I have PID controlled HX and DB. As a general rule, I run them so the group idles about 4°F below brew temp. I flush to about 4°F above brew temp, lock and pull. It's been a long time since I Scaced them, but the espresso seems to taste OK.

I just upgraded from a Gaggia Baby to a QM Andreja which is an HX machine. From what I've read here, Coffee Geek and Chris Coffee you need to do a cooling flush to lower the water temp otherwise it would cause the shots to be bitter. When you first start the flush you get steam and some water then it gradually comes out straight water and with a measuring cup under the group head I usually get 4 oz of water. Then I place the pf and pull a shot. If you're doing back to back shots you don't need to do a cooling flush every time only if the machine sits ideal for any length of time. Not sure of the water temp just yet, I haven't got a thermometer that fits into the group head yet.