On Sunday, 13 November 2016 18:55:56 UTC, Andrew Gabriel wrote:
In article ,
David writes:

Brief background; visiting a friend with very old central heating -
reminds me of what was in our last house when we moved in in 1984.

An old Glow-worm 85 100 floor standing lump of iron. Kettles like a really
kettly kettle. Radiators of various vintages, some with suspiciously cool
bottoms.

It hasn't been serviced recently (then again, these are so simple that
there isn't much to service compared to modern boilers). This also
suggests it might do with a flush and some inhibitor.

If it's not room-sealed, then it really should be checked every
year, as it can suddenly build up soot through the heat exchanger
which causes incomplete combustion and emission of carbon monoxide.

Also, in such a system, a flush and inhibitor might clear out some
scale sealing leaks, particularly in the boiler itself.

Recently knocked up a Pi-based controller for a Kingfisher cast-iron
lump, to try and improve efficiency of an old system for a friend.
That has a pumped heating circuit, but a gravity hot water cylinder
coil. It didn't have a roomstat or cylinder stat originally - it does
now, and remote control/monitoring over the Internet.

In principle I suppose you could monitor flu gas temp and turn the flame on and off frequently to keep the exchanger just above condensing, and thus get a big improvement in efficiency.


NT