Well, my first inclination was jointing compound but I'm not convinced that quantity would be in the cylinder. My second thought is foam insulation used during the tank manufacture which has somehow got inside the cylinder.
Maybe the most likely explanation is the compound used to help release the tank from the mould when it was pressed which wasn't cleaned off.
I would follow Proptec's advice and contact the cylinder manufacturer and ask their opinion.
Hi Barkinglama, I have something very similar if not identical to this happening with my hot water supply. Did you ever get to the bottom of what was causing it and how it was fixed? Thanks for any help, Alan
I know this thread is very old but I came across it trying to solve a near identical problem. I don't suppose either of the people with the problem ever found a solution? Worth asking but I'm not holding my breath as the thread seems to have been abandoned!
I had something very similar when I moved into my new house which had had new c/h & hot water installed ~10 years previous. Both the upstairs and downstairs shower filters on the hot water were getting clogged every few days/couple of weeks. The stuff clogging them was like a mushy white paste but it dried once removed and collected to a white powder looking similar to the soap powder you would out in a washing machine. As the gunk was only on the hot water side the local water authority said it must be our heating that was the problem not their water supply, I could see their point.
Anyway as the shower filters weren't easy to access or clean I installed a much easier to access filter (Toolstation 16650, see picture) directly on the hot water tank outlet. That immediately stopped the shower valves getting clogged as it filled up with the white paste and was easier to access/empty every week or two when we noticed the hot water pressure dropping. What we couldn't understand was how the last occupier had coped with this as he was no good at DIY and would not have been opening/cleaning filters every couple of weeks. Anyway and very strangely, after a few months the filter stopped getting clogged and this is no longer a problem for us. I still check it now and again and find the odd grain of this stuff but nothing that causes a problem. If I had to guess I'd say it was something from the hot water tank manufacturers but when I called them they couldn't fathom it and I must say I struggle to say how it would come from such a tank. Anyway I still have the white powder if anyone's interested or wants a photo etc.
Thanks so much for replying! The gunk I have sounds exactly the same. The inline filter looks a great idea. Saves taking several things apart. I'm going to get one fitted and fingers crossed it clears up just as yours has. Thanks again!
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