Descaling intravenously

Equipment doesn't work? Troubleshooting? If you're handy, members can help.
BaristaMcBob

#1: Post by BaristaMcBob »

I have a Bezzera BZ10 heat exchanger machine, which I'm about to descale. The instructions say to use the pump to fill the boiler with descaler solution. Afterwards, I need to pump through clean water several times to rinse out the chemical.

I thought of a better way. With a cold machine, I would attach a silicone tube to the hot water wand. Blowing air into the steam wand would force the water out along the silicone tube. Once the flow starts, siphon action would clear out the remaining boiler liquid.

For rinsing with clean water, I can just pour it back in through the hot water wand, using my silicone tube and a funnel, leaving the steam valve open for venting.

Anything wrong or naive with this method? Seem to be an easy way to flush multiple times.

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BaristaBoy E61

#2: Post by BaristaBoy E61 »

Why not just use the pump to circulate the clear water? You're using it to circulate the descaler?
How are you going to clear the pump and everything else in the water circuit?
"You didn't buy an Espresso Machine - You bought a Chemistry Set!"

BaristaMcBob (original poster)

#3: Post by BaristaMcBob (original poster) »

Yes - good question. I will use the pump initially and also for clean water to clear out the pump and all the various copper tubes. However, since I cannot drain, say 25% of the liquid in the boiler, I need to rinse the boiler at least 7 times to dilute the descaler down to non-toxic levels. That's a lot of pump action and a lot of time. Also, with the pump, I can never exceed the level sensor.

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BaristaBoy E61

#4: Post by BaristaBoy E61 »

I have descaled our machine quite a few times, less frequently now that we've installed an in-line BWT filtration system. I've always done it by switching from water line inlet to reservoir for both citric acid and filtered water flushing. Draining the steam boiler has always been by turning the machine 'OFF' after bringing it up to temperature then opening the hot water spigot till as much hot water or hot water with citric acid can be flushed. Turning the machine back 'ON' causes the pump to activate with the PID preventing the heater elements to power 'ON' until the steam boiler fill probe has been satisfied.

We have never had any damage to the pump or pump motor. The only serious incident to occur has been flakes of scale washing through the steam boiler fill solenoid valve interfering with its ability to fully close (seat). This was after the machine was set back to 'Water Line'. Fortunately, my wife was present and saw this happen with the accompanying counter top flood. We quickly turned off the ¼-turn ball valve inlet to limit damage. Had we not been home this surely would have been a kitchen disaster.

We have since installed a Leak Detector with automatic water line cutoff. Something that I would recommend to anyone that has their machine direct plumbed. It is just as important and goes hand in hand with proper water filtration.

Attached is a pic of the solenoid valve body with tiny flakes of scale large enough to have an insurance claim should this occur while unattended.



"You didn't buy an Espresso Machine - You bought a Chemistry Set!"

JRising
Team HB

#5: Post by JRising »

I shouldn't bother entering the conversation because someone's going to argue and I don't want to be responsible for what people do...

But why are you going to descale your machine? Because it has a lot of calcium in it and you want to get it all out, or because you want to see what happens when you put some descaler through and want to see what comes out? Both are good reasons.

If you just want to descale to see what you get, then sure, blowing it out the hot water wand and looking at it is ideal and easy.
If there's a lot in there and you truly want to remove it from the boiler, just blowing the liquid out of the hot water wand won't be completely successful. If there's a lot of mineral build up, it will crack and fall from the ever-changing element as it heats and cools. Flakes will fall to the bottom of the boiler. If you rock the machine while blowing the liquid out of the hot water tube, you may get the small flakes through, you may get the large flakes stuck in the valve.

Once you've proven that you have A LOT to remove from the boiler, blow out as much liquid as you can to make the machine lighter and the boiler closer to empty. The heating element removed leaves a good sized hole to dump the worst of the minerals out through. Depending on the configuration of your machine, you may want to block the vacuum breaker, working on rolled-updisposable towels or one of those soft plastic milk crates in the utility sink so that the machine doesn't get scratched, dump everything out of the boiler. Position the machine with the element-opening facing down, feed a thin semi-rigid tube up into the boiler through the element opening, blast and flush everything out. Turn the machine with the element hole up and fill the boiler with descaling solution. Let it sit long enough to remove whatever was bonded to the boiler, dump it, turn it element hole down again and blast it all out with the narrow hose. This will leave NO acid in the boiler.

"But that sounds like a lot of work"... Yeah, I stand firmly by the advice that if you don't want your machine to be a disposable machine, you can give it softened water.

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HB
Admin

#6: Post by HB »

BaristaMcBob wrote:Anything wrong or naive with this method? Seem to be an easy way to flush multiple times.
Without getting into the merits of descaling or avoiding the need to descale, there's another easy way to flush the steam boiler, assuming you have a rotary pump that can run for a few minutes.
  1. Remove the top to give you access to the steam boiler's water level sensor probe.
  2. Open the steam and water wand valves.
  3. Remove the wire to the water level sensor probe so the pump will run continuously. Eventually the boiler will fill to the tippy-top and water will flow out of the two wands. IMPORTANT: The steam boiler and its gauge aren't rated for brew pressure, so the wands must be open to avoid pressurizing them beyond their rating.
  4. If your espresso machine doesn't have an overflow tube for the vacuum breaker, you'll need to pull up on its pin so it seals. Otherwise water will gush out (don't ask me how I know :lol:).
Apart from the relative ease of the above method, it has the added advantage of flushing the steam and water wand. I recommend removing the steam tip and water wand filter head to avoid clogging.

REMINDER: If you're not comfortable working on your espresso machine, stop! Find a qualified technician.
JRising wrote:Once you've proven that you have A LOT to remove from the boiler, blow out as much liquid as you can to make the machine lighter and the boiler closer to empty.
My approach above assumes mild scale buildup. When in doubt, get an inexpensive bore scope that connects to your phone and inspect the boiler to determine if it's mild scale or "chunks of rock" time. :shock:


Oh no! Time to call for help...
Dan Kehn

BaristaMcBob (original poster)

#7: Post by BaristaMcBob (original poster) »

My water is very hard. I can see scale build up in my tea kettle after a few uses. My espresso machine uses a reservoir with a BWT filter to help soften the water. I've also avoided using the hot water tap, so as to avoid adding more water to the boiler. In hindsight, I'm not sure that was a good idea, as the release of steam will increase the concentration of minerals in the boiler.

So why do I want to descale? Well, I turned on the hot water tap and brown water came out. After two boiler flushes, the water still has a brown tint to it.

They say espresso machines should be routinely descaled every 4-6 months. Mine has never been descaled. It's been two years.

The tips above are excellent, but I'm in no position to remove the cover, or remove anything from the boiler. The reasons for that are complicated, so I am presenting that as a given. I'm limited to pumping and flushing.

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HB
Admin

#8: Post by HB »

BaristaMcBob wrote:I've also avoided using the hot water tap, so as to avoid adding more water to the boiler.
Unfortunately, that allowed the mineral concentration to increase over time. Steam boilers should be flushed frequently for that reason via the water wand (or drain, if equipped), otherwise scale buildup is inevitable. Hard water in, distilled water out. :( If you have hard water and you're seeing discolored water, that strongly suggests there's significant scale accumulation.
Dan Kehn

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BaristaBoy E61

#9: Post by BaristaBoy E61 »

I would say that the greater risk at this point is not to descale. You should achieve a good result with a 2-yr old machine even if your water is very hard.

It might be nerve-racking the first time but I've found that it even improved the operation of the group.
"You didn't buy an Espresso Machine - You bought a Chemistry Set!"