Hello everybody, I've got a 1981 La Pavoni Proffesional machine and just a couple of days ago I had it sent for general service and some small reparation. After I got it back, the machine was functioning differently. Before the reparation, my pressure realise valve was not working at all, I would easily reach 2BARs without valve releasing any steam. Now the valve starts hissing and realising steam around 1BAR creating kind of a 1BAR pressure equilibrium. I noticed that, as a consequence, my temperature is slightly down which is OK when pulling 2 shots in a row. Could anyone tell me if described functioning of the safety valve is consider to be normal and why is that?

Thanks in advance
Goodbyejoe

It sounds like two things are wrong here.

All "Professional" models have a pressurestat. It should be set to turn off at a bit less than 1 bar. I like to adjust mine so that the boiler temperature is between 115 and 116C. (This is about 0.7 bar gauge pressure here at 300 metres above sea level.)

The pressure relief valve should only release steam when the pressurestat fails. (This is to prevent catastrophic failure of the boiler from over pressure.)

rpavlis wrote:The pressure relief valve should only release steam when the pressurestat fails.

Yes. Make sure that the person who serviced it did not replace the spring with one intended for an older Europiccola, which is supposed to hiss in the neighborhood of 1 bar. If you disassemble the safety valve your spring should have about 6 coils. If it has about 12 coils, they installed an incorrect spring.