Machinegun_AK Senior Member Joined: 28 Jun 2011 Posts: 1 Location: Vancouver Expertise: I live coffee
Posted Sun Jul 15, 2012, 12:09am Subject: Dezcal discolors brass?
I am restoring a mistreated Bezzera BZ02. It's mostly cosmetic on the outside but the inside I notice there is some scale build up on various things. One thing that seems to be having trouble is steam pressure release valve. It's the valve that is open until the boiler starts to get to temp and then is suppose to pop up and seal. I believe this valves allows the machine to warm up without having to bleed the steam wand like in the Oscar. Other have written that scale can cause this valve to stick and not seal and consequently generate a hissing sound. What I noticed was that it was sputtering water inside the casing. I took it apart and dunked it in a packet of Dezcal mixed to 1L of what as instructed on the packet. While it did clear out all the scale build up, I noticed where the scale was replaced with some discolor brass. I'm guess it was brass to begin with. The color is now pinky, almost copper like. Is this normal? Or perhaps was it always copper but with some sort of brassy coating that got corroded by the limescale?
the part you are describing is the antic vac valve as opposed to the pressure release valve.
the discolouration is quite common,basically when brass, copper and acid are together they can react and deposit the copper onto the brass
it wont have an effect on how your anti vac valve works, i guess its purely cosmetic, if you really want to you can polish it to try and get the brass back.
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