There is much information on HX pertaining to older HX designs with no restrictors in the TS and flushing routines. But there is little hard data on the newer designs with PID and restrictors in the TS loop. I have no idea whether my machine behaves similar to all other Pro 500 PIDs; I can only assume it does.
I plan to do more SCACE measurements.. I just received the unit today.
The SCACE measured 211.9 in my steam test so my meter is pretty accurate (I can spit in the sea). It gives 57g of water in 30 second pull. Within specs I believe.
My workflow. (NO flushing!)
Machine on for 60 minutes..
SCACE/PF installed only in last 15 minutes (I know a weak point of the measurements.. will fix on next round)
Pulled shot #1
Steamed 5 oz water to 140F (simulate the cappo/latte)
2 minute wait
Pulled shot #2
Wait for rebound for 12 minutes
Pull shot #3
My PID is set for 253F (Profitec only recommends 248)
Shot #1.. the brew water averaged about 197. Not too bad. I was shooting for 200F. Eric thermometer about 4 degrees higher than SCACE.
Shot #2 .. before this shot, I steamed a small pitcher of milk to 140F. Then pulled shot #2 at about the 3 minute mark. Here you really see the effect of the restrictor in the TS. My brew water never got above 193. (Here's where I was hoping that Erics reading during the middle of shot was the same as the brew temp... it wasn't)
Shot #3 .. I waited until the group thermometer to read at least 196 and then pulled the last shot. This took an additional 12 minutes.. This shot was about 196.. maybe just a tad cool.. I likely could have waited longer.
Very preliminary conclusions..
1) Tables in HX manuals that attempt to relate boiler PID settings to brew water are not useful. By Profitec's manual, my brew water should be about 204F.. I am at almost 10F below that.
2) Eric's thermometer is an excellent tool for relating the actual brew water temp to its reading. (about 4 deg high with my workflow)
3) The rebound in these newer designs with restrictors is unforgiveably slow (maybe the milk steaming had much to do with this). I do not believe anyone should pay $2k5 (Can) and only be able to make 2 lattes in 20 minutes.
How on earth could you ever guess at what the brew water temperature was without at least a group thermometer? It is an essential part of using the newer HX designs.. Because of manufacturing tolerances, I suspect that each instance of this machine might behave thermally slightly different.
However, the SCACE does confirm my 'gut suspicions' ever since I've owned this machine. If I am shooting for 200F in my brew water, I've been using this machine for 18 mo and still have not found a workflow that will produce that. I'm confident I now will; but HX designs with restrictors might not be a very user-friendly beast.
4) Manufacturers could do way, way more to make HX designs more user friendly. Specifically, (especially on E61 groups), there needs to be a temperature monitoring point near the screen of the group. Then this machine would be much easier to use. I see the MaraX has attempted to address some of these issues.. not sure how their new design works.
Interestingly, the Profitec Pro 500 now can come with flow control by replacing the mushroom, but that eliminates the possibility of installing a group temperature thermometer (unforgivable! and shows a lack of awareness on Profitec's part of the necessity of a group thermometer).
Feel free to criticize the experiment.. I'm very new at this.. I will bump up the PID and add some flushing before shots to see the effects and will publish over time, if there is interest.