Monkhai

Could be a temperature sensor, the thermostat or the Water pump possibly.

M is the tea bag free revision A is the original one I had with a fairly solid tank Other letters are different revisions, with I imagine variations on a theme of tea bag or other silicate. You want an M revision if you want a tank without the bag. That is unless your dealer says the system shows another new revision that does not include the silicate.

Anyone got one and if so what are your thoughts? they seem to have a capacity about 50% larger than most others of the same size and currently around half the price of an equivalent Bosch.