Pump Pressure

baristar

Hi all,
I have recently noticed that I am getting a lot of variation in pump pressure when I install my machine in different places. It is a Lisa 2 group. I was wandering what are the factors that affect the pressure. ie Sometimes I can only crank it up to 5 bar other times I can put it wherever I want????

FreshCoffee2

Without running the machine personally & checking functions, the first things that come to mind are: a) Your water pump might be failing OR b) You are not readjusting pump pressure at each diff location to account for the diff incoming line pressure that you are hooking into AND / OR, you are not running a water pressure limiting valve (and therefore you are at the mercy of the variations in mains pressure in different locations anyway. Therefore: Fit machine in a location where it will not be moved for a while, RESET THE PUMP PRESSURE to pump at say 9 to 10 bars during the brewing of coffee, with one only group running. Keep the machine under observation whilst in normal operation, over the next few days. If the line pressure indicated on the gauge varies from the figure as set, & assuming the water supply is reliable and consistent....the pump is probably failing. If this is the case it will eventually just stop pumping. In addition if this is the case, the pump is probably quite noisy, squeaky, rattly already. If on the other hand the indicated pressure in the gauge over the period of observation behaves itself, then the pressure variations you are seeing are most probably the result of you moving the machine around to diff locations, suffering the effect of the differing incoming mains pressure on those locations. If you are going to move a machine around & hook up to local water supplies, you need to adjust the pump pressure accordingly every time so that it will compensate for the prevailing conditions (ie local pressure). This is the reason why esp machines should always be hooked up with a pressure reduction valve which first reduces mains pressure, and the pump repressurises internally to the pressure we require to brew esp properly. So if you are not running a pressure reducting / limiting valve (350kPa) you should be (followed by suitable filter). Ofcourse notwithstanding all the above I've left the most obvious thing til last!!! If you remove machine from its mains (reduced) water connection and simply "throw" the end of the pick up (feed) pipe into a container of water, your pump pressure is likely to read only about the pressure you noted above because it has no "boost" behind it from the mains. When you do that, you are supposed to adjust the pump pressure up to compensate. Is it possible we could have an update from you to let us know how you get on? Regardz, FC.