I have wondering this for a while and guess there is no better place to ask.

On my Aurelia you can have the pump turn on during auto fill or use line pressure. I have always used line pressure because it obviously saves the pump and is less noisy.

My question is this; does using line pressure instead of the pump affect the shot performance at all? And why is this an option?

Silly question but I simply don't the know the answer

I have no experience with the Aurelia, but in general: it should make no difference whether the boiler autofills from pump or line pressure. If autofill engages during a shot, it could affect the pressure at the brew head (even then, a rotary pump should have pressure to spare). So save the pump for brewing, and use line pressure for autofill.

Ellejaycafe wrote:On my Aurelia you can have the pump turn on during auto fill or use line pressure. I have always used line pressure because it obviously saves the pump and is less noisy.

The La Marzocco Strada has an option for refilling the steam boiler via line pressure or pump and a similar option for the tea dispenser (i.e., it can pull only from the steam boiler or mix steam boiler water and fresh water). Since I have it plumbed in, I see no harm in letting the mains pressure do the work for refilling the boiler. When it comes to pulling shots, the pump is always engaged.

Ellejaycafe wrote:My question is this; does using line pressure instead of the pump affect the shot performance at all?

If your Aurelia offers the option of preinfusion under mains pressure, I would be tempted to experiment with preinfusing with 4 bars pressure for 3-6 seconds before the pump engages. If it's simply to refill the steam boiler, there's no need for the pump unless there's no positive pressure (i.e., drawing from a bottle).

HB wrote:The La Marzocco Strada has an option for refilling the steam boiler via line pressure or pump and a similar option for the tea dispenser (i.e., it can pull only from the steam boiler or mix steam boiler water and fresh water). Since I have it plumbed in, I see no harm in letting the mains pressure do the work for refilling the boiler. When it comes to pulling shots, the pump is always engaged.


If your Aurelia offers the option of preinfusion under mains pressure, I would be tempted to experiment with preinfusing with 4 bars pressure for 3-6 seconds before the pump engages. If it's simply to refill the steam boiler, there's no need for the pump unless there's no positive pressure (i.e., drawing from a bottle).

The pump comes on to fill the boiler only when I use the tea dispenser. Other than that it only comes on when pulling a shot.

My question was really does it affect the pre infusion. When I pull a shot the gauge goes up to about 6 bar for 4-5 seconds then I hear the pump kick on and it slowly goes up to pressure. By doing this I am assuming the machine is using line pressure for the pre infusion since I don't hear the pump come on right away? It seems as if the machine is doing just as you are saying. Using line pressure for the preinfusion for 3-6 seconds.... I get very consistent shots and can't remember the last time I had a spritzer or channeling using a bottomless. i have that mains pressure set at 4 bar with a regulator (if i take it any lower the machine tells me it has trouble filling).

I have never tried using the pump for the auto fill because I simply didn't know this was option. I became curious about it when I realized that my machine NEVER refills the boiler no matter how many shots I run or how much steam I use. The only time the pump engages to fill is when using the tea dispenser... Which makes since because it's drawing a lot of water instantly.

I don't think I can adjust the amount of time or pressure for preinfusion. It has the soft infusion system. But I guess I have been using line pressure preinfusion this whole time and not the built in pump preinfusion. I will experiment with it this week and see what difference it makes. Thanks for the clarification on what exactly is happening! I'm learning more about the machine everyday and that's a good thing.