I've been playing around with my digital thermometer and came up with this data.
With the PID set to maintain a boiler temp of 253F:
1) After sitting idle the group temp of my ES-1A is 214F
2) A 35 second purge (~14 oz) drops the group temp to 200F
3) It's best to wait ~5 secs after the purge before pulling a shot
4) The group temp stays between 199F and 200F during a 2 oz shot
5) It's best to wait ~10 secs between shots for the HX to reheat
The tests were done using a Tenma 77-7712 digital thermometer and a type K thermocouple that had been calibrated using boiling water.
The thermocouple was held in the portafilter by a sponge that was cut to fit inside it. The thermocouple was pushed through the sponge and looped to keep the thermocouple tip 1/4" from the top of the grouphead. The sponge permitted water to be retained inside the grouphead at the same time it permitted excess water to exit the portafilter.
I'm trying to borrow a Scace device so I can compare test results. I'll also be capturing the results of my tests so I can graph it for those of you who're visually oriented.
