The water filling the brew boiler isn't cold, but rather preheated in the steamboiler at a higher temp. My OPV goes off at 11 bar. Dennis
-----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of bobvilax2000 Sent: Thursday, February 25, 2010 9:35 AM To: Brewtus Subject: Re: Rotary Upgrade - Group Head Pressure rising "cold water is filling up the boiler and then being heated, as it is heated it expands, as the boiler is saturated there is not a lot of room for the pressure to be absorbed resulting in high pressures being created quite quickly, sort of like a hydraulic brake system. Pressure get to 12Bar and the OPV valve opens to release it. Once temp stabilises, no more increase in pressure. " Bingo. If there is no opv then you would have burst tubes. My rotary B1 rotary doesn't drip after a shot but, like all espresso machines, drips almost the whole warmup since the entire machine is heating from about 20C to 93C, which means a lot of water expansion and pressure. I forget what I have my opv set to (Brewt 1, so no brew gauge), but it's probably around 12psi as well. - -Barrett -- You received this message because you are subscribed to the Google Groups "Brewtus" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/brewtus?hl=en. -- You received this message because you are subscribed to the Google Groups "Brewtus" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/brewtus?hl=en.
