Hi All,

I've just unboxed my MCAL and I don't like the inside of my sight glass--it needs a good cleaning. Does anyone know the best way to do this? Alternatively, can I just fill the machine with a citric acid solution and let it sit, followed by some good flushing?

There's nothing wrong with the machine; it's just been boxed up for 2 years and deserves a good cleaning.

Thanks!

Edit: Changed title to better reflect question.

That's what I did with my 2nd hand one. I also turn the heat on for a bit (but just to warm things up) as the citric acid solution works faster when warm. Let it sit for a while. I then flushed some through the group. Fresh water was used to flush things and before you know it, voila done.

Mark

If the sight glass is still cloudy after the citric you can take off the pressure gauge and use a bottle brush or fat pipe cleaner and touch it up from the top through the gauge fitting. No new seal required, maybe some teflon tape on the thread when you reinstall the gauge.

Thanks guys.

I'll try the citric acid and see how that works first. What solution do you suggest? I have some, but I only have 4oz left.

Thanks...

You could try a table spoon in a boiler full of water. The acid is relatively weak and you can't really mess it up. That's why we like it so much. It also tastes much nicer than say vinegar should you not rinse as thoroughly as you should.

Mark

I have had some experiences with citric lately and would generally recommend fairly short exposures if you are at all concentrated. Mhoy's tablespoon per boiler is about right if you are going to heat cycle with citric. I wouldn't leave it in the machine for no more than 2 or 3 hours as it really does attack brass and at 2 hours you can empty and flush, see how the sight glass looks and decide if you want a repeat. If you soak the external parts in citric too long you can lose some chrome, particularly if the chrome is thin from some previous owner scrubbing with some abrasive....don't ask me how I know.
Again, I would say, fairly dilute with repeats rather than a strong blast all at once.

You could just remove the glass and treat with citric separately.

It's soaking now. I used a tablespoon of citric acid. I'm cycling the heat to get things started, and I may heat it up about an hour in or so to keep things hot. After two hours I'll empty and flush everything and report back.

Thanks for all the advice guys...

Green water...interesting. Wasn't expecting that. Citric acid never turned my pancakes green...

So I flushed the machine several times, but in the end I took off the pressure gauge anyway. But I'm not happy with the water coming from the group--it has a slight yellowish tinge to it. It's not clean.

I also pulled out the piston and cleaned the chamber, as well as the dispersion screen, gasket, and portafilter. I can't think of anyplace else gunk is hiding--do I need a better (or just another) cleaning of the boiler?

Thanks...

Did you flush the group through with citric acid? Should have cleaned it right up... And if you used the machine after the cleaning, the yellow water is due to coffee oils, you need to flush some more water through in that case...

The blue water syndrome is probably due to copper dissolving from the acid, not dangerous for you or your machine if you don't drink it...

Is it safe to use Urnex Cleancaf in these machines? TIA

Cathi wrote:Is it safe to use Urnex Cleancaf in these machines?

Sure, it's nothing more than citric acid and mild detergents with a 1000% markup.

Madroaster wrote:Green water...interesting. Wasn't expecting that. Citric acid never turned my pancakes green...

I think the blue-green color is the citric acid removing some of the oxidized copper. Not an issue to worry about. Have used a citric acid solution on the Elektra for descaling maintenance probably half-dozen times. No problems with the machine yet. Only scaling problem or maybe use fatigue has been the Mater pstat. Piston gaskets and grouphead gaskets replaced due to normal wear with use. Well built and easy to maintain machine.

Yellow tinge water? Have you pulled the piston assembly out for inspection. Check for coffee residue, mold at the piston base, if gunk found trapped between seals/gaskets maybe time to replace them. Hopefully it's just some residual water in the boiler, transfer tube that can be purged, dumped and flushed out.

Madroaster wrote:I'll try the citric acid and see how that works first. What solution do you suggest? I have some, but I only have 4oz left.

When I asked the folks at the Reneka factory about descaling my Techno, they recommended the gentlest possible approach. That was to use 5 grams per liter and leave it cold for a day or so, then repeat and rinse.

Best,
David

narc wrote:Yellow tinge water? Have you pulled the piston assembly out for inspection. Check for coffee residue, mold at the piston base, if gunk found trapped between seals/gaskets maybe time to replace them. Hopefully it's just some residual water in the boiler, transfer tube that can be purged, dumped and flushed out.

Yeah, I pulled all that out. It all looked very clean, although I did clean it of course while it was out; I do that quite regularly.

I think you're right that it was just some residual water; it seems to be running clean now.

On a performance-related note, I'd forgotten what a steamer these things are...much better than my Europiccola was. The shots aren't as good still, but practice makes coffee, if not perfect.