Nuova Simonelli Appia no water out of brew heads

#1: Post by **mrcoffee** » July 12th, 2015, 1:39 pm

We have had this machine since new here at our shop and just recently the one group head stopped working all together. We continued to use the 2nd brew head and after awhile it too stopped working. Both heads where pulled and descaled, both brew solenoids click when activated. Pulled one flow meter and checked, was clean with minimal scale and spun freely.
3.5 to 4 bar incoming water pressure with 9 bar when pump kicks on. Could the pump pressure regulator be bypassing but still show 9 bar when activated? I don't even get a trickle of water out of either head when the dosing button is pushed, the pump runs and the pressure is where it should be, but no dosing, with maybe a few drops of water after shut off in the drain. Could the boiler be so full of scale it needs delimed? Would a bad flow meter cause this?

#2: Post by HB » July 12th, 2015, 2:12 pm

I don't know the particulars of the Appia, but if you've confirmed there's no blockage of scale at the brewhead, it sounds like the grouphead solenoid is stuck shut. Have you considered calling a repair technician? No insult intended, but if you're asking for help on a site called home-barista.com, you may be out of your depth. To your questions:

mrcoffee wrote:Could the pump pressure regulator be bypassing but still show 9 bar when activated?

Yes. The brew pressure reading is typically from a tee prior to the grouphead, i.e., it measures the pump output, not what arrives at the brewhead.

mrcoffee wrote:Could the boiler be so full of scale it needs delimed?

The Appia is a heat exchanger espresso machine. The steam boiler may be filled with scale and the heat exchanger too. No way of knowing without inspecting.

mrcoffee wrote:Would a bad flow meter cause this?

Since the brew pressure is 9 bar and you've confirmed the flow meter isn't blocking anything, I don't see how.

July 12th, 2015, 2:37 pm

This machine shares parts with its smaller brethren. And also operates on similar principles as the smaller machines. There was a similar post on here with the same problem and it was a clogged flow meter orfice. The brew heads are flooded, pressurized and hot, just no pressure to pull shots. Everything else works, steam wands, heating element, pump even the brew solenoids click and release a drop or two of water after shut off. And again, both heads and brew valves were pulled and descaled. Would 1 faulty flow meter cause this?

July 12th, 2015, 3:54 pm

I have an older NS 2 group, and about the only thing I can think of off-hand that it shares with NS's home HX's (Oscar, Musica) is the portafilter and an excess of plastic

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Just kidding - you are right, the principles are the same. Follow the water, and if following the water doesn't get you anywhere, then you have to follow the electrons - and control boards are where commercial volumetric machines are very, very different from home machines.

If the brew head is pressurized, then it sounds like you have to follow the water inside the brew head, i.e., what the brew solenoids are activating and the "soft-infusion" system. Mine is so old that it doesn't have soft-infusion so I can't be of more help, sorry.