I fired up my Conti Prestina, after years of it sitting idle and a subsequent rebuild, and it is getting too hot. Every valve and connection on the machine was heavily calcified, so I'm thinking the pstat, a Sopac, is the same and stuck/frozen. Are these repairable, and if so, is it worth trying to fix it? If it isn't the original pstat, it has been on the Prestina for at least ten years, about five years with very hard water being run through it, and the other five with it parked.

Also, the only other part on this machine that I did not rebuild or replace, except for the manometer, is the anti-vacuum valve. Do I need to consider that as a culprit in the overheating?

Many thanks.

You should descale your vacuum relieve valve just as routine maintenance, I like having a spare so I can just swap them out and go, with no real down time. But if they get plugged up, you'd likely only see false pressure and a machine that doesn't heat since it will think it's already at temp based on that false (higher) pressure.

I believe I've read here before that Sopac's are a bit more prone to the ills of scale deposits. You can get a Sirai really cheap from Allann Bros, or a replacement version (likely to be a Mater) for very cheap. It's a great machine to not have up and running, I hope you get it fixed soon.

Thanks Tom. Incidentally, I did try adjusting the pstat, but to no avail.

Hi Albert:

The Jaeger PSTAT is identical to the old Sopac. It's available at Chris Coffee. It's very easy to order one and swap it out. Fitting a Sirai PSTAT isn't easy. There's not much room inside the case and you need to create new pipe to accommodate it. To my mind it's not worth doing.

If you do want to try and revive your old Sopac you might use a turkey baster or dropper and invert it to introduce a 50:50 solution of white vinegar and water.

On my Prestina I'm taking temperature control a bit further and have added a PID without permanently modifying this collectible machine. This allows me to easily set temperature without reaching for a small analog dial behind the drip tray. When I want to brew coffees at higher temperature the Jaeger PSTAT limits my top end. I'm swapping it out for a Ceme PSTAT* for that purpose and will fit my machine with a resettable temperature safety switch for protection.

* Bought at Stefano's Espresso Care and available with adjustable or fixed deadband.

Tried reviving the Sopac with vinegar solution, but that didn't work. Ordered the Jaeger from Chris' Coffee. Hopefully that will do the trick.

While the pstat is off, I'll try to fashion a new bracket to hold it steady, although it is quite light and the rigid copper tubing seems to be enough to hold it. The original pstat was held by a bracket that was attached to one of the boiler bolts, but I didn't like having to remove the bolt to do this swap; the boiler actually leaked a bit while the bolt was off. So I'll find another way to brace it without having to disturb the bolts that keep the boiler together. Who knows how many other times I may have to remove the pstat in the future....

I'm having trouble uploading some pics of my Prestina in progress, but will post them as soon as I figure it out.