Post By Dimal
Post By MrJack
Post By gazza
How do you measure brew pressure for OPV adjustment?
I am currently in the process of adjusting the OPV in my e61 HX machine to get the optimal 9bar brew pressure. the machine gives me > 12bar peak from the factory which is on the high side.
I know in order to get 9 bar at the brew head I will need to get 10bar at the pressure gauge. but the thing I am not sure of is how do you measure the 10bar, I had adjusted the OPV to get around 10.5bar at the gauge by using a blind disc in the PF. however when I actually make a coffee the reading is a bit lower (<9 bar).
Can someone shed some light on this?
Sounds close to perfect mate....
No need to muck around any further...
One way of looking at it:
Originally Posted by symphonie
When you have the blind in, there is no flow to the group. The pressure at the pump discharge is limited by the OPV, and the pressure at the group will be the same.
When there is no blind in, there is flow through the group. When the water is flowing, it drags along the pipe wall, losing energy to it. This manifests as "pressure drop" (meaning the pressure at the outlet of the pipe is lower than at the inlet.