Pressurestat replacement

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drH
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#1: Post by drH »

So I've noticed the pressure deadband getting wider on my Maximatic after it's been on awhile. Occasionally it peeps into the red zone which is probably an indicator that I should change the pressure stat.

My water is excellent (zero water plus third wave packet) but I understand that these Mater p-stats sometimes just need replacement regularly. I've had the machine in regular use for less than two years.

My question is- does this happen as frequently on other machines? I don't read a lot about people replacing the P-stat on the Linea Mini every couple of years. What's the difference there?

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howard seth

#2: Post by howard seth »

I used to replace my Mater pressure stat on my 2006 Elektra Semiautomatica every few years - and even more frequently when I used not so clean water: Brita pitcher filter water was not clean enough for the Mater - so I switched to RO water - which helped - but those stats still failed, just not as quickly.
Howie

drH (original poster)
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#3: Post by drH (original poster) »

Is it possible that if you add a relay to the pressure stat it will extend the life? Do the pressurestats fail this frequently on commercial machines like the Linea Mini as well? I'm pretty sure the LM also has a Mater.

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baldheadracing
Team HB

#4: Post by baldheadracing »

My guess is that it has something to do with location (above/below the water line) and operating temperature. Machines with a reputation for being hard on the Mater pressurestats - Elektra Semi's, Pavoni domestic levers - have the pressurestat located below the bottom of the boiler and in an area of little to no air circulation (so the pressurestat gets hot).

As an aside, there is a low-voltage version of the Mater that can, for example, drive a solid-state relay. I believe this is what La Marzocco has used. (I don't know what they use now.)
-"Good quality brings happiness as you use it" - Nobuho Miya, Kamasada

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cannonfodder
Team HB

#5: Post by cannonfodder »

drH wrote:Is it possible that if you add a relay to the pressure stat it will extend the life? Do the pressurestats fail this frequently on commercial machines like the Linea Mini as well? I'm pretty sure the LM also has a Mater.
Commercial machines and some prosumer use Sirai or PID controllers. Even the larger Sirai will eventually fail. They are contact points and the points will wear over time or the diaphragm will go bad. The consumer Mater and the like will fail more often but are also inexpensive to replace.
Dave Stephens

RKRobinson

#6: Post by RKRobinson »

Any recommendations on a pressurestat for a pavoni pub 1 group? Currently it has a matter xp110 but its never been as stable as Id like. When I bought the machine I replaced it but it lasted only a year.

Richard