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Permalink Reply by Al Sterling on June 30, 2009 at 7:23pm

Brady...... I'm not a tech in this industry, but know from years in hydraulics and pneumatics that opening the bottom-point flush valve on any closed liquid or air system is all about letting gravity and the system pressure force small solids out of the system. You may be very familiar with the magnets attached to the oil pan drain plug? All the heavy-ferrous chips, G*d forbid you have any, will travel and settle at the lowest point in the system. I'm due to break into my La Spaz, and plan on doing whatever I can to avoid having "chunks" of mineralized solids break away and into the lines and valving.

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Permalink Reply by Phil Proteau on June 30, 2009 at 8:51pm

Draining without descaling seems a little pointless. As steam evaporates from the water in the boiler, the mineral content stays behind. A dedicated brew boiler, like in a LaMarzocco, will not accumulate as much as a steam boiler, because the water passes through without steaming off. A lot of the accumulated mineral deposits int a steam boiler, however, will form a delightful sludge in the steam boiler, while calcium and lime will crystallize on the element (reducing it's ability to transfer heat to the water). You should be descaling every year. Even if you have a water softener, you have accumulation since you cannot use completely soft "zero" water. So there will always be mineral build up in the steam boiler.

Some boilers have convenient drainage valves on the bottom side, others don't. I am a big fan of unscrewing the pressure safety valve on the top of the boiler and inserting a siphoning tube (1/4" John Guest tubing) to drain the boiler when they don't have a bottom valve.

There is an urnex product made of concentrated citric acid for descaling. There are some chemical descalers for engines and such that you should not use for espresso machines. Lemon and lime juice won't help much, don't ask me how I know.

It's not that hard to do, but you need to wait till after closing time. And bring six pack of suds or soda.

Good luck!

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Permalink Reply by Brady on July 1, 2009 at 6:24am

Thanks guys. I will do this.

A neat trick that I happened upon when descaling the Astoria in the shop (up on its end, heating element removed) was to remove the endcap from my hombrewing "racking cane" (rigid 1/2 inch plastic tube a couple of feet long) and send the end all the way to the bottom of the boiler. The flow of water through the siphon let me vacuum the mud off the bottom, just like a pool vacuum. It would be impossible to get the entire bottom if I was only accessing through the vacuum breaker and pressure safety valve, but I may try this technique again and see how it works, even on a machine with a boiler drain.

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