Thank you Oilhead, it is actually in the 15mm mains cold feed into the heat exchanger, that has the Sentinel device in. I have an ADEY Magnaclean and inhibitor in the primary circuit. I am hearing that electrolytic inhibitors are not much good, and my experience confirms that.
I am considering...
Thank you for your very helpful reply, I shall follow your recommendations. I didn't know rubber washers were used, and presumably they don't need to be done up so tight. And thanks for making me think about water softening, there is presently just a Sentinel Electrolytic Scale Inhibitor which...
I replaced the plate heat exchanger 18 months ago and despite the supplied fibre washers and good cleaning of pipe faces, the top supply (mains pressure) joint has always weeped a little, despite re-tightening. With the heat, it quickly evaporates but now the build up of calcium is making me...