Monday, 8 April 2024

La Pavoni OPV & pressure stat

 Maintenance / repairs etc.
You need to find out what machine you have
 since the new anti-vacuum OPV body is different from the old standard steel ball OPV.
The old machines don't have anti vac, so at startup you need to release some steam to get it up to the correct temperature.
La Pavoni changed the design of the anti-vacuum valve again in 2021.

To open the valve up you need two thin #16 wrenches.
One needs to fit around the M12 boiler nut (that attaches the valve to the boiler).

The safety valve is composed of a few parts:

18. Safety valve body part no. 396751 
       (chromed not gold). 
       Suitable for LP's that have 
       this valve with a M12 thread.

20. Spring, part no. 311407 
                  (8 coil spring - new style)
                   Part no. 311406 
                  (15 coil spring - Old style)




19.  Valve plug (anti-vacuum), 
       part no. 396754 R  (new style)
       Valve plug, part no. 371416 (old style)


The #311406 (15 coil) is the one to buy if you have an old dual element non-pStat machine .
The 8 coil spring looks like the same one that has been used in pressurestat-equipped machines since the early Professionals..: 



This is a new style anti vaccuum plug 
(part No: 396754)















This is the old style valve 
part no. 371416











The earlier machines without PSTATs constantly vent steam through the OPV, so it's not a good idea to leave them coasting.

The build up of scale can effect the valve.
If your late model (post mil) constantly vents steam the OPV is probably stuck, perhaps with scale. 



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This is a modern Pressure Stat for the La Pavoni Professional and Europiccola lever machine models that have a single element. It's function is to control and regulate the pressure inside the boiler.

The safe max pressure for the LP boiler is 1.1bar.

Part No 451308 (pressostato)

The pressure stat was first used in 1974/76 (Professional).
1991: Europiccola added.


There are a few versions, so you probably need something different if your model is old.



The addition of the pressurestat ended the need for "dual" switches and two heating elements, and allowed a single "on/off" switch (red) with a power light.  The pressure was usually set to .8-1 BAR at the factory.  (Industry standard.)  


The Pstat can be adjusted by turning the screw.















In the pic on the left the pressure stat switch is 12.
It connect to a pipe (11) that feeds into the boiler.
Over the years, this may get blocked with scale, so make sure to descale your machine regularly.














These are pics of the base of a 1991 Professional.
Needs to be restored. Lots of rust.

The pressure stat is at the bottom in the middle.

This old pressure stat isn't adjustable.
So it will be good to swap it with a new one which will allow you to change the pressure.








Some close ups








----------------
settings
generally 0.7to 0.8 bar for brewing is fine.
To froth milk, try to get to 1 bar.








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This is the pic of the underside of a new 2024 La Pav Europiccola

To get to this, you need a torx T20 screwdriver bit.
The bit must have a centre hole.



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