Ok guys, hopefully this will be the last question I'll ask for help with my BZ40 project (though no promises!).

With the heaters disconnected I am getting extremely fine air bubbles in the brew water, so fine in fact they remain in suspension for a long time and the water looks cloudy. The pump sounds normal, and not as if cavitating, and I have heaps (too much in fact, but it's temporary just for testing) of inlet water pressure. I'm wondering if this is normal and what causes them? I'm thinking it's the flow restrictor (think Bezzera call this a jet) and wonder if it will settle down eventually. Since the machine was stripped to component level it will clearly have air in the lines and if this is not normal may disappear with time.

Cheers,
Pete

Does your tap water exhibit any of these bubbles? How long does it take them to rise to the top and dissipate?

You might google "dissolved oxygen" for some helpful information on how those bubbles can get in there and what they mean.

Generally, you must have a source of air infiltration or a high level of air already in the water as it comes through your supply lines. Forcing the air/water mixture through a restricted orifice can cause enough turbulence to divide up the bubbles if the already exist. Bubbles already in suspension can also be caused by a dramatic reduction in pressure within the closed system which makes the water boil; the oxygen will break loose at a very low temperature. Add turbulence to low pressure and a leak and you'll get cloudy water.

There is an echo cardiac test known as "bubbles." I just had one. Ultrasound monitor watches the heart while a nurse moves a small amount of saline from one syringe to another. One of the syringes is empty so it's pulling the saline into a vacuum which causes the water to boil. The repeated movement between the syringes creates so much turbulence that the oxygen saturates the water and makes it cloudy. Then it's injected up your arm and the bubbles make the heart chambers light up. It was very cool.

I'd suggest you examine the connections to your machine very carefully for a leak. Reseat all brass or plastic connections with new Teflon tape.

david boise ID