I have had my VBM Super Double Boiler for about three months, now, and am beginning to think about descaling it once, just to see what has built up in there. I doubt it is very bad, as we have soft water, and I still run it through the Brita filter before pouring it in the machine. My question is, though, are there instructions for the Double Boiler? I have found the instructions for the VBM Domobar Super HX, but the procedure will certainly be quite different with the two boilers.

Also, how much citric acid do you add for each liter of water?

Thanks!

There is not much difference. You can drain the steam boiler by heating it, turning off the machine and open the water tap. That will get 80 or percent of the water out. Brew boiler is a different story. You will either have to open the machine up and drain the boiler by opening the supply line into the boiler or take the vacuum breaker out of the top, stick a hose in it and siphon the water out. Put your bucket full of descale solution by/under the machine, put your supply line in it and turn the power switch to the first position to power up the brain box. You machine will fill the boilers, then follow the other directions. Heat, soak, flush, fill, heat soak, flush and rinse the boilers out 3 or so times with water to get all the acid out. However, after only 3 months, I would not bother unless you have very hard water (200 ppm+). My water runs 180 ppm and I only descale every six months and even then it is probably not needed but I do it as part of my own PM schedule.

Almost forgot, I believe it is 2-3 tablespoons per gallon of water, 3 if you have heavy scale. I get my citric acid from a local home brew store. A pound will last for years.

Thank you for the information. I suppose I will wait, as our water past-Brita is quite soft. I descale our hot-pot once a year, and it does not really need it, then.

Actually, on a PID machine with a thermal sensor right in the water, I would suggest a minimum once a month descale. I have recently learned that the sensor tends to build up scale sooner, rather than later. And, it affects the sensor's ability to react to the delta in the water temperature of the coffee boiler. So, for the coffee boiler, we recommend once a month. Just run descaling solution (4x the strength through the grouphead) and make sure to not get the solution on the finish of the machine. To properly displace all the solution from the coffee boiler on the Vibiemme Double Domo, I would suggest running two full tank fulls of softened water through the head. However, not continuously so you avoid burning out the pump. I would run about a half a reservoir full every 30-60 minutes through the grouphead.

For the steam boiler on the Vibiemme, it is ok to go longer (3-6 months) because there is a full size pressurestat there. This is one reason why we are hesitating to place a thermal pid sensor on the steam boiler of the Vibiemmes - with the even higher temperatures of steam boiler, there is even a 'potentially' greater likelihood of scaling on the sensor.

So, to clarify, for the monthly coffee boiler, do you recommend I first find a way of emptying the boiler, then run the citric acid solution (4x strength) through the group head, or would it be acceptable to just insert the feed and back-flow tubes into 1.4 liters of acid solution and run it through the group head in two batches of .7 liters, let sit 30 mins, then run 2.8 liters of softened water to purge?

YasBean wrote: by YasBean on Wed Mar 03, 2010 11:34 am

So, to clarify, for the monthly coffee boiler, do you recommend I first find a way of emptying the boiler, then run the citric acid solution (4x strength) through the group head, or would it be acceptable to just insert the feed and back-flow tubes into 1.4 liters of acid solution and run it through the group head in two batches of .7 liters, let sit 30 mins, then run 2.8 liters of softened water to purge?

Was this question ever resolved? I'm interested in the answer as well.

Theoretically, scale build-up on the sensor could affect boiler temperature.
Practically, environmental effects and themal distance from sensor to group make it largely irrelevant.

Anytime one deviates from standard operation, there is a risk of error and damage.

I have yet to descale my Vibiemme and after 2.5 years the shot profile, as measured by Scace and taste, is unchanged.

If 1st-Line has documented e61 SHOT performance degradation due to DB sensor scale, please share it.

I thought this was a matter of maintenance and longevity (of the machine, not necessarily the user!) , rather than shot performance as such.

It is.

On the HX, I can measure the effect of scale on the shot inter-shot temperature change.
See Scale, HX Temperature Stability and a bit o' PID

Using the same bottled water, no change is detected on the DB.


Brew boiler element after 6 months of daily use with no descale. Boiler looked no worse.
Real soon now, the DB will be torn down for a photo session of possible neglect

Sadly, there is far too much hooey on the www. On ALL topics.