modding the expansion valve setup

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modding the expansion valve setup

Postby cbcrema » Wed Jul 20, 2005 1:42 pm

When i adjusted the expansion valve on my andreja there was one thing
i wondered about:
The Expansion Valve is located after the Heat Exchanger.
When pulling the shot at least half of the water that goes through the
pump leaves the expansions valve and is piped back to the fresh
water reservoir. Since this water goes through the HX bevore leaving
though the expansion valve it will be brewing hot. Hot water going to
the reservoir seemed a bad idea in my eyes. So i changed the piping
to the drip tray.
Done that i realized that too much fresh water is dumped by that way :(
More water than necessary goes through the HX, so more scale and less
temp. stability.
i was not happy..

So i had to do the first mod to my andreja.
I changed the ULKA pump to a Fluido Tech with expansion valve.
So now there are two expansion valves in the system.
One after the pump, the max. pressure is set here. dispensable water is
piped back to the reservoir.
The second one is after the HX, i adjusted it back to 13 bar. the hot water
from here goes to the drip tray (if there will be any pressure above 13
bar..)

unfortunately i only managed to bring the fluido tech expansion valve
down to 11.5 bar. The shots i made so far tell me that this is not a
problem however.. The "Hochland Rassico" Arabica Blend tastes like
sweet chocolate :D

i hope this information was interesting for you :?
bye
Christian
QuickMill Andreja (boiler insulated/cold water expansion valve)
Rancilio Rocky (teflon tape helps)
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cbcrema
 
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Joined: Mon May 30, 2005 9:21 am
Location: Stuttgart / Germany


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