Hi,

I recently got one of Eric's thermometer adapaters to fit on my Isomac Rituale, but am seeing some odd behaviour in the temperatures I am reading. I am using the supplied digital thermometer currently.

To give a bit of background, I have just stripped and re-built the machine after finding considerable scale buildup. The E61 group has also been fitted with new brass valve parts (due to wear) and all new springs and seals. I checked for any sign of leaks after the re-build.

The pressure stat is currently set going from 1.1 to1.3 bar.

What I see is this:

With the machine on for about an hour I saw a group idle temperature of 211F, as my p-stat is set to run 1.1-1.3 bar I expected this to be a little higher, but not exactly out of the ballpark. I then flushed water through the group down to 185F (which took about 30 seonds), the temp bounced back to about 202F and then started to fall (as expected) however it carried on falling for about 2 minutes to about 190F and then took another 3 minutes to climb back to 198F. This doesn't seem to add up given my p-stat setting. I would suspect a problem with the thermosyphon action, but having just stripped and descaled evrything and I know that it is completely clear, I am confuesd!

Even if I only flush down to 195F the temp still falls for around 2 minutes, and another 2 back to 198F.

I have checked for leaks but cannot see signs of any. Tha machine does not have a restrictor, though the lower aperture in the group is smaller than the upper, but I presume this is a standard group feature.

As the group gets pretty much near the idle temp expected I am guessing that the thermosyphon action is fundamentally working, and the fact that the reverse action works, seemingly a little too well, other than my boiler pressure gauge being massively incorrect (I might buy a gauge and check it against the original one) I cannot think what the explanation could be. The only other things i can think of are that whilst the boiler sits level side to side it does not quite upright looking end on, so in theory the HX is stiing a little lower than ideal. Could this or water level in the boiler affect things? I presume there is a theoretical ideal water level for a machine but can find no info on the for the Isomacs.

I did see some plots that Eric did on a Rituale that behaved very differently, mcuh quicker rebound time.

Ultimately I guess it is not a problem as such, I can just adjust my flush routine accordingly, but it is always a concern when a machine behaves differently to others of the same type.

Anyone have any suggestions or simlar experiences with Isomacs?

This is a chart from some measurements taken today.
I flushed from an indicated group idle temperature of 202.5F (temperature peaked in teh flush at 214.5F) down to 913F (which took 25 seconds) which is when the cahrt starts. My pressurestat is cycling between 1.1 & 1.35 bar., protafilter out, measurements made using the digital thermomter from Eric's kit.


Very strange, especially the long low dip in temp. I'm beginning to think that the HX has some problems still...