Thanks! I'll give it a shot. If it heats up enough to make steam go out the pressure relief valve then at least I know I'm on the right track.

I might have to get a new boiler tank. There's a coral reef in there. I got a lot out but there's still a lot of limescale. I tried 2 Tablespoons of citric acid to 1 liter of water and filled it up for a little over a 1/2 hour but it didn't do much. The funny thing is that I've been using filters that claim they eliminate limescale. Maybe it was in there slowly growing from the previous owner.

When I descaled my 2 group machine, it took over a kilo of Dezcal mixed in quite a number of gallons of water over many days to get out the limescale.

Thanks for the info. I'll order some. Can the dezcal hurt the metal? I only left the citric acid in for 1/2 hour because I heard that it can hurt the metal. How long do you leave each batch of dezcal in? Can the dosage be increased to make a stronger solution without fear of eroding the metal away?

Thanks again!
Joe

I added water to the top of the scale and Dezcal to the boiler and then connected one of the elements to 110V to keep the mixture warm and let it sit for hours. Every time I changed the mixture I removed the heating element and removed whatever scale had come loose. In my case for the first few time I could not remove the element due to scale and just removed all the large chunks of scale from the element I could. If I was close enough to hear the solution boil, I'd connect 2 elements till it boiled and then disconnect one of them. I had the boiler out of the machine sitting in a large plastic tray on the patio while doing this.

I'd fill the boiler with undiluted white vinegar & let it soak for 12 hours or more if it's really scaled up. Unlike the citric acid the vinegar does not need to be heated to be effective.

I have the heating element out so I could go with the distilled vinegar if it won't damage the metal. I'm guessing it's all copper. Thanks!

The vinegar isn't going to damage the copper, I've used it many times on brass & copper parts.

Okay thanks! I have the Heating element out. I can lean it on it's side and put the vinegar in. My only problem when I did that last time is that it leaks up top on the pressure release valve I think. It should stop eventually I think. I guess I could remove it and plug up that hole.

I haven't made much of a dent. Should I fill it up with the Dezcal and install the heating element to get more of the limescale dissolved or is that going to risk more problems with the pipes?

I think this was after a 1/2 hour of hot water and citric acid...



This is after more than 12 hours of the undiluted distilled vinegar...

That's pretty nasty scale/deposits. Got access to a bead blast cabinet? If not I'd try leaving the vinegar in there for a day or two.