Originally posted by Coffee Kid link=1157414445/15#20 date=1158146183
Some dual boilers use the steam boiler to pre-heat the water which passes into the brew boiler (this is the case with some prosumer dual boiler machines - dont know of any commercial ones that do this!)
So with this type any changes in steam boiler temp affects the temp of the brew boiler (and the recovery time of the brew boiler).... Remember that prosumer machines have boilers 10% the size of mine..... and smaller heaters to boot (they have to run two boilers off 10 Amps where mine runs off a 25 Amp circuit for one boiler).... with these - changing steam boiler characteristics will have some effect on the brew boiler.
The reason that the water to the brew boiler is preheated is to help that boiler get the volume of water to brew temp faster (because of the small element - all caused by the fact that these machines MUST plug into a 10 Amp outlet for consumer convenience.
Some prosumer machines (and commercial machines) which have two totally seperate boilers would have no problem if you increased the steam boiler pressure.
Out of interest, whilst purchasing my grean bean supply today, I checked out the latest commercial high volume 3 group.....
It has a boiler per group - yep thats right 3 boilers for brewing - and I assume a large boiler for steaming,,,,,,
;DRequires at least a 30 amp supply (three phase recommended).....
But still doesnt look half as good as my La Cimbali!!

..... this can be adjusted by "tuning" the process but is a complex proceedure. (reducing the temp of the boiler will likewise reduce the group temp)...
But would be nice to play with one :P
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