cannonfodder wrote:It really depends on the solution you use. I use a commercial descale solution that is very strong. I descale a commercial boiler that was many years old in 2 hours and it was clean as a whistle. That same solution will dissolve the edges off of copper bolts and hex heads if you leave it in solution to long, it is very strong stuff.

So the soak time needed will depend on the solution used to descale the machine, the severity of the scale and the temperature of the water. The hotter the water, the more aggressive it works.

This is correct with one caveat. With commercial descaler, you will not neutralize the acid to a safe level with the scale in the machine, so one needs to watch the time. The 1.5 to 2 tablespoon citric per liter solution will be neutralized by heavy scale, and isn't all that aggressive to begin with, so it can be left in for a while. I go overnight on cold machines and 2 to 4 hours on a hot one (depending on how lazy I've been in scheduling).

The usual caveat -- this citric solution is roughly 50% to 75% the strength of lemon juice, and it'll pick up light scale. If you have a heavily scaled part, or a valve, orifice, or piping junction, that has scaled severely (even if it's not that much calcium), it won't do the job in a reasonable amount of time. You'll need to take a part like that out, sit it in a commercial or higher concentration of citric, and remove the chunks as they come loose. I've had emails on parts that would scale severely in a few months even with fairly soft water. A simple citric flush didn't do anything for them. These generally are found on new models, since such parts' designs are revised when they show up.

I have a force fill switch on my Tea for descaling, works great. I tried a 3 position switch with a grounded third position that disabled the autofill entirely, so it wouldn't mess up my shots. But after I forgot to put it back after a hectic session, I gave up on that idea.

Speaking of autofills -- since they carry current, they can attract scale (and an odd pasty sort of grunge) even in soft water. It's worth cleaning off the wand once a year, when doing a descale. Make sure to use a marker before removing it, so you know how deep to push it back.

Guys - Once, in haste, I removed the autofill probe without knowing what it was - so I don't know what level it should be at. Is there a way to guesstimate the depth it should go to? I thought I once read the boiler should be half full in normal operation (see - I'm a half full kind of guy).

Geoff

Somewhere between 50 and 75%

More water = more steam longer
Less water = quicker recovery

You may want to look at Ken Fox's Boiler Fill and Shot Temp Stability

Without an MOS, raise the sensor side of the machine.
- Open the steam valve and let the pump run until it stops or water runs out the steam wand
- Close steam valve and level the machine

I'm running steam. This is an EXpobar Pulser. How long should I let the steam run? It's freaking endless. I just left the steam open, drained an oz or so from the water tap, which activated the pump. I shut it, the steam immediately died down (cold water entry), and I shut the steam. Is this OK, is it overfull now?

The Pulsar has a vertical boiler with the level sensor amidships, so tipping the machine is not going to have much effect.

If you pull a cup of water from the hot water tap with the steam wand open, the boiler will overfill slightly due to water expansion, maybe 1 or 2%.

Cool, thanks. That's pretty much what I did. After, I drained and refilled the boiler 4 times, as I only got a pint out each time. I'm not sure how much the boiler holds, but I figure it's more than that. I got lots of silt/glittery bits out, until the last time, which was much reduced. Keep in mind it'd been 5 years without a descale.

I guess I should do it again soon, huh?

A tech note that hasn't been mentioned on this thread -- siphoning is easier than using the water tap

If you are willing to open the machine up; then removing the vacuum breaker or safety valve and siphoning the descaling solutions and rinses in and out of the boiler, saves a huge amount of time and effort. This is also the easiest way to prep machines for storage or transport.

For instance, I descaled a machine Tuesday, and only needed to rinse the boiler once after siphoning out the citric acid, since I could get the boiler completely empty except for a few drops. When using the hot water tap, it takes three to four rinses, along with waiting to build up the pressure for each rinse round.

Ohellno. I'm not a tinkerer. I break stuff.

cannonfodder wrote:When dealing with acids, better safe than burning a hole in your tongue and dying a slow death from taste testing to see if you got all the acid out, IMHO

I really can't imagine you getting anything but indigestion from drinking citric acid flushed out from a machine, but I can't imagine it tastes very good either so might as well flush it out of there. I'd personally would be much more worried about the metallic ions that the acid dissolves from the oxides on the inside of the boiler, copper isn't very good for you...

Great write up I've been meaning to descale my Anita and finally got around to it last weekend.

I'm not very mechanically skilled and was nervous to disconnect wires, glad I could get by without doing that.