In article .uk,
Ed Sirett writes:
Are these units made by Drugasar (Drugasol?) If so, that make had
the peculiar 'feature' of requiring power to be applied to keep the
heaters off. Which means they come on in a power cut and are generally not
liked. This might be the mechanism they work by, as I've only ever taken
them out.

Furthermore with infrequent use they get in churches and other public
buildings, the flue gases tend to condense on startup and rot the heatX.

My wall mounted one was a Drugasar. The proportional control
on the thermostat was amazing -- my thermometer was 0.1C
resolution, and it kept the room temperature abolutely
spot on within that 0.1C resolution.

I knew they did electric remote controlled versions too (mine
wasn't), but I didn't realise it used the same crude (but very
effective) mechanism that I had added to mine. And yes, this
did mean it came on during power cuts! I did look into
replacing it with a newer Drugasar at one point, but they no
longer did a 4kW one, and largest domestic one had dropped to
something like 2.5kW at that time, which wasn't enough to heat
half the house that the previous one did, or the large commercial
ones for churches and the like.

--
Andrew Gabriel