Descaled Elektra Microcasa a Leva. Steaming is now poor. [SOLVED] - Page 2

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boren (original poster)
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#11: Post by boren (original poster) »

The vacuum breaker seem to work, but the period between it starting to let off steam/bubbles and locking in the up position is only about 2 minutes. Is there any way to service it myself, or is it a must to replace it?

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rpavlis
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#12: Post by rpavlis »

I would check to see if much air remain in the vapour in the boiler. Place a glass under the steam wand and open it. (Tall olive jars are good for this.) If you get bubbles that rise to the surface for more than a moment, there is still air in the vapour of the boiler. If the pressure gauge fall significantly while you do this it is a further sign that this is true.

Problems with the vacuum breaker normally stem from it NOT closing rather than closing early. When there is trapped air without a functioning vacuum breaker on a pressurestat machine like the MCALs, the boiler temperature is only about 100C, perhaps a bit less, when the pressurestat turns off the current. (This is a result of Dalton's law of partial pressures.) After bleeding off the air in such a machine it will take a minute or two for the boiler to reach the 115-120 degree temperatures normally used for steaming. The "auto bleed" from vacuum breaker valves can easily be shown to be a bit incomplete by the "bubble" test described above. (Really they are NOT even designed to auto bleed, they are designed to prevent the boiler from being under vacuum when the machine is turned off. It is just an accident that they also mostly auto bleed the system.)

When I open the steam valve momentarily after the pressurestat first turns off the gauge falls about 0.2-0.3 bar. After a very short bleed and a bit of time to get up to temperature and pressure, opening the steam valve momentarily causes no discernible pressure drop at all. The bubble test on mine always shows bubbles for perhaps 5 seconds when the boiler is full, more when less filled. After bleeding the only bubbles that appear are from air in the steam wand, and they are gone in a second.

Vacuum relief valves close when water condensing on them or rapid steam passage pushes the valve upward. This obviously occurs before all of the air in the boiler gets swept out. Some group designs also trap a lot of air in the group, the design of the MCAL group, however, precludes this problem.

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baldheadracing
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#13: Post by baldheadracing »

boren wrote:The vacuum breaker seem to work, but the period between it starting to let off steam/bubbles and locking in the up position is only about 2 minutes. Is there any way to service it myself, or is it a must to replace it?
Given you just descaled, a bit of something in there is most likely. I would just unscrew the breaker and put it in some diluted vinegar for a couple hours, and then rinse thoroughly.
-"Good quality brings happiness as you use it" - Nobuho Miya, Kamasada

boren (original poster)
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#14: Post by boren (original poster) »

Yes, it makes a lot of sense, especially since after descaling I rinsed the machine at least 10 times, turning it upside down in the air and (gently) shaking / swirling it every time. A large amount of lime residue went over (and probably through) the vacuum breaker. I'll do what you suggest.

boren (original poster)
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#15: Post by boren (original poster) »

Problem solved! Detaching the vacuum breaker and leaving it in Durgol for a few hours did the trick. Thanks for all the helpful replies. You saved me a visit to the lab :)

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