Just had new Grant 26e combi installed (by same plumber who installed Aquadial water softener). Central heating system filled by unsoftened water as normal but all other water, including water going into boiler for hot water goes through the softener - I thought nothing of it as trusted plumber but am not told (by different plumber) that I can't have softened water going into boiler at all. Read up and it looks like this is only true for boilers with aluminum heat exchanger, but Grant web literature indicates 26e heat exchanger is steel. Anyone have any info on whether I can or cannot run softened water through a combi boiler - and if not why not. Thanks