conikal wrote:
so ..." the boiler remains hotter for longer ( and therefore the HX)" ... may well influence the shot temp to be hotter.
Except that we are agreed the boiler is NOT hotter. The length of time it takes to drop by the approx three degrees from high point to low point (determined by pstat deadband) is extended, so it also remains cooler for longer (the second half of the time that the heater is off) if you look at it that way. Yes, my mind works in mysterious ways. I know I am a tad geeky at times, As derrilex noted, the heat LOSS has changed, but that is evenly balanced by the heat input due to the pstat doing exactly what it is meant to.
conikal wrote:
Also, my personal belief is that on most m/c's... ( E61 particularly),.. the actual HX temp is not critical and its the temp of the group which controls the shot temp. So be careful that your insulation doesnt cause the group idle temp to increase significantly.
And that, I suspect, is a far larger factor than the boiler insulation when it comes to shot temp. I have looked again at the photos posted earlier and it looks like derilex has basically gone around filling every crack he can get to, tradie that he is 🙂. Barely room in that casing for anything except insulation. This has effectively insulated the HX loop (but not the head obviously), hadn't really focused on that first time around. Rereading the cycle times posted I am amazed it manages to get up to the high end of the temp range in seven seconds, that is a pretty responsive element. My Grimac takes 35 seconds on time (1650w) and the Azkoyen took 25-30 seconds (2400w). Even uninsulated, my boiler takes about 1min 45 sec to drop back down. I shall be interested what difference I see with insulation as it will happen soonish. If I get down to 5-6% like derrilex, I'll just leave the machine on and idling a lot more often just in case I need coffee during the day. c-man - commercial machines certainly ought to be stable, the environment they are in demands it. I would have thought that the domestic machines in this price range would also be stable - that big hunk of brass is what provides stability during the on/off cycles of the element, and certainly ought to flatten out small temp variations during the cycle.
