another_jim wrote:If your boiler has an easy drain, do that once a month; in this case add a little regular water back to the distilled, since the autofill needs it. If you flush, enough minerals will stay in the boiler to keep the autofill happy.

Maybe for more than the autofill. The reservoir sensor in my GS/3 appears to be conductivity based, so I'll need to add some tap water to the RO when flushing to keep the machine from stopping and demanding that I refill the reservoir. It'll be interesting to see just how low I can go on TDS and keep the sensor happy.

I love how that guy wrote this:

I will consider this email to be fair warning, and will maintain a copy in my records.

But never issued a request anywhere in his letter.

Some people just have too much time on their hands...

Would you say that if someone was using only Brita water, that measured 30ppm for 1 month at a time, and confirmed it was 30ppm for the period, that one would still have to run RO water thru to be sure not to have any scale buildup ?

another_jim wrote:If your boiler has an easy drain, do that once a month; in this case add a little regular water back to the distilled, since the autofill needs it. If you flush, enough minerals will stay in the boiler to keep the autofill happy.

I'm not positive, but I don't think there is an easy drain. I believe I will have to use the hot water outlet that I understand is connected to the bottom of the steam boiler. I'm still learning about this Duetto. I appreciate your comments.

Vince

I flushed the steam boiler on my GS/3 today, and it takes *way* too long using the hot water tap. First of all, you have to remove the tank (which has a tricky tube clip), dump the water (it won't let you run the tank dry), reinstall and fill with RO water. Then you have to get into program mode and turn off the tea water pump so tank water isn't mixed with the boiler water at the hot water tap. The hot water button is one of the programmed volumetric buttons, so you only get a cup full of water each time. You can go into program mode and do a long pull through the tap, but there's a time limit on that. Finally, when the boiler pressure falls, you have to wait for it to build up again to draw more water. With a 3.5L boiler, it takes a really long time (not to mention at least two tank fills.)

Luckily, the GS/3 steam boiler drain is easily accessible. I would recommend a weekly drain and fill with RO instead of flushing. You just remove the left panel, take a cap off a ball valve, slip a tube over the valve, and open the valve to drain the boiler in one easy step. If you want a thorough drain, you have to tilt the machine, which is pretty heavy. I would probably do this once a month, when the brew boiler gets drained.

I spoke with LM USA about descaling today. I noticed the manual conspicuously does not contan any instructions for periodic descaling. I suspect that enough damage has been done by improper descaling that they no longer recommend it in writing. I point-blank asked what they recommend, and was told that if the tank water is maintained at 3-4 grains, which they feel is a good compromise between hardness and taste, and the boilers are drained at least once a month, that the machines can go several years without descaling. If the steam boiler is drained more frequently, the time frame is even longer. They didn't say what to do after "several years", but my sense is that they expect the boilers to be serviced or replaced by an authorized service tech at that point.

My plan is to use water with a TDS on the order of 30mg/l (maybe a little higher if I determine taste is affected), drain the steam boiler and fill it with RO water once a week, and thoroughly drain both boilers once a month (refilling the steam boiler with RO.) As of now, I'm not planning on descaling.

My plan is to use water with a TDS on the order of 30mg/l (maybe a little higher if I determine taste is affected), drain the steam boiler and fill it with RO water once a week, and thoroughly drain both boilers once a month (refilling the steam boiler with RO.) As of now, I'm not planning on descaling.

Dick,

For this plan of draining the steam boiler once a week, I am curious to know how much use your machine gets ?

Also, as I understood, for the other boiler in the GS3, that making tea or several cups of tea is a way of draining that boiler and has some effect on reducing scale.

I will be at the LM factory in 2 weeks from today and will be asking them about this subject.

misterdoggy wrote:Dick,

For this plan of draining the steam boiler once a week, I am curious to know how much use your machine gets ?

Also, as I understood, for the other boiler in the GS3, that making tea or several cups of tea is a way of draining that boiler and has some effect on reducing scale.

I will be at the LM factory in 2 weeks from today and will be asking them about this subject.

My daily usage varies from a low of two shots and one steaming, plus at least two large tea water mugs, to a dozen shots and half a dozen steamings when I'm dialing in new coffee and/or experimenting (plus the tea mugs.) I would characterize this as very light duty for a GS/3. I do, however, leave the machine on for about 13 hours per day. Seems to me that the less use the machine gets while it's sitting there heating, the more opportunity there is for scale to build up in the steam boiler. True, the steaming and two daily tea water pulls are helping, but they're not making much of a dent in the 3.5l boiler capacity. I think the boiler water needs to be replaced once a week. I would do a weekly flush, pulling it in by running the hot water tap, as Jim suggests, but that takes a long time. It's quicker and easier to do a drain-without-tipping. Also, rather than refilling the boiler with my low TDS RO+tap water, it's better to fill the steam boiler with RO (not the brew boiler.) When the tank is then refilled with low TDS water, it will introduce minerals into the steam boiler, but much more gradually than if it was full of low TDS water. This is Jim's recommendation as well.

First of all I want to say thank you to Jim for starting this thread.

I purchased the ZeroWater pitcher/filter which comes with the TDS meter as recommended and it works as advertised.

I have been using Poland Spring which I buy locally at Costco and it has tested to be 42 ppm TDS. I tested my steam boiler water by using the hot water tap (after shutting off the tea water pump as mentioned by Peppersass) and let it cool to room temperature and it had 77 ppm TDS. After flushing about 4.5 liters of ZeroWater mixed w/ Poland Spring to achieve approximately 5 ppm TDS, I was able to bring the steam boiler water TDS down to about 19 ppm TDS. I have to agree with Peppersass, that it may be simpler in the future to just drain the steam boiler on the GS/3 and refill with ZeroWater/Poland Spring of approximately 5 ppm TDS to keep the tank and autofill sensors happy. Anyway, great thread and recommendation for maintaining your TDS levels to minimize descaling needs. I am very pleased.

As Peppersass mentioned, La Marzocco recommends draining both the steam boiler and brew boiler monthly. I clearly understand the need for the steam boiler, but I am not so sure I understand the need/reason to do so for the brew boiler. Does the brew boiler accumulate minerals that wouldn't be flushed from the normal use of making espresso and flushing of the brew group? How would draining the brew boiler be any different?

Joe

Thanks for the response Jim.

I am using Poland Spring with 42 ppm of TDS for brewing which I know is not ideal for espresso (too low?), but currently tastes fine to me and should also minimize scale deposit.

Fortunately both the brew boiler and steam boiler can be easily drained on the GS/3, and I plan to do so in the near future but it is a 2 step process. I need to drain the steam boiler via a ball valve and hose into a bucket, fill reservoir water tank with 2-5ppm TDS water, then turn the machine on so the autofill kicks in and fills the steam boiler. After the steam boiler is filled (with probably 2 full water reservoir tanks), I would then turn off the machine and drain the brew boiler via the OPV into the drip tray, fill the tank with straight Poland Spring (42 ppm TDS), and so on. I was just wondering whether it was necessary to drain the brew boiler as often as the steam boiler, since minerals don't theoretically accumulate. Since it is recommended my LM, there must be a good reason, so I should probably take the extra time and drain the brew boiler as well.

Thanks again.

Joe