# Understanding the sequence (what happens when)



## grumpydaddy (Oct 20, 2014)

As the proud owner of a classic I have my tech head on just now and want to understand just what is happening whilst the machine is running.

I have a rotary pump, a few solenoids and relays, some heaters linked as one, level switches/sensors. You get the picture I am sure.

Currently I have this tank fed from a remote tank that relies on the pump within the machine to do its thing to get water where it needs to be. It will be mains fed at a later date but in the interim I ordered a small pump to put some pressure on the inlet.

Why bother you may ask, well, it occurs to me that such a pump could be used to pre-infuse once I understand what is happening at each stage of the shot.

Just now it seems that the pump runs when the tank fills and when I switch on the "pull" but I wonder if I can introduce a delay in that cycle whereby the only pressure seen at the group would be the 2.5-3.0 bar introduced by the remote pump.

Has anyone got this information or done the work already? It is all new to me and I can work it all out given time, it would be a whole lot easier if one of you has some sort of fault finding flow chart to hand.


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## Bruce Boogie (Dec 1, 2014)

Great idea, the more we understand the process, the better we should be able to make a decent coffee.


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## espressotechno (Apr 11, 2011)

Fracino Classic or Gaggia Classic ? Fracino has a rotary pump......a greater pump pressure can be achieved if your water tank(s) are level with or higher than the pump.


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