"Jeff" wrote in message
...
Can anyone explain how boiler modulation works, its benefits etc and the
same for weather compensation

Modulation is like a light dimmer, the level of output can be varied, so the
boiler can be on at a low level continously.

The alternative is like a normal light switch which can be off or on. You just
keep the boiler on for long enough to generate the amount of heat that you need.



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Michael Chare