I believe there is a one way valve associated with the pick up (suction ) tube. I would contact Chris coffee service and talk to them about it. Simple fix from what I understand

For what it is worth.. There is a small brass check valve on the discharge line after the pump discharge and between the boilers. There is a tiny O-ring on the plunger of it that gets worn out if you take this check valve apart. A new check valve is 20 something bucks from Chris Coffee, however a 5 cent O-ring fixed the problem. Thanks for the help.

You figured that yourself or Chris helped you out?

Chris told me I needed a new pump for 200 dollars when the rebuild kit for the pump is available from the manufacturer in Connecticut for 34 dollars. I ordered the rebuild kit and it still didn't work, so I stopped bothering with Chris' Coffee and decided to take everything apart.. Yes, I figured this out myself.

Hi 37train,

I am still on the road to buy a stock new AD 3.0 for 1950 € (very goog price discounted initially from 2600 € and after that from 2100 €).

Having in mind your issue and poor diagnostic provided by the dealer, would resomend to buy this machine or to buy one Expobar Brewtus with vibration pump and to forget about AD 3.0.

BTW, before you buy Alex, did you try the espresso from Alex and had you compared it with the espresso prepared from Brewtus, or another vendor? Had you firmly decided to buy a rotary pump machine instead of vibration pump equipped one? I have read so many threads in HB, but I would like to have your opinion on the matter.

I am asking you, because I am an espresso fan who want to buy a DB machine, but nevere tasted the espresso from Alex Duetto. Only have read tha is superior. I tasted only a shot from Expobar Brewtus IV with vibration pump in a coffee shop and I was impressed from aroma and espresso taste compared with my Ms Silvia which could provide such God shot VERY rarely. (I make the shot my self in the coffee shop with my brought Mazzer Mini Electronic).

So, that it is. I am on the road to decide if it is worth to buy an Alex or Brewtus IV with vibration pump is quite enough. My setup in home do not allow me to plumb the machine, so I will use the water tank only.

Thank you very much for your time to read this huge post!