A bit like saying:
" I understand how a shoelace is tied, what I don't get is why you tie a shoe lace".
Think of a car. It has a minimum RPM of usually 800 before the engine has to switch off/stall.
Boiler is the same..,. Although the minimum varies greatly between different units for reasons we won't go into here, if only to keep Blowhardgreen in his box.
Boiler is set to 70 degrees.
When the system water reaches 70 degrees, the boiler tries to lower the amount of gas burned (its RPM) to keep the engine running that bit longer.
IF it can't, then it switches off but leaves the pump running to dissipate the heat usefully.
To prevent the boiler yoyoing on and off, there is a program built in to minimise/maximise various things like MTF, efficiency etc.
Some boilers let you tweak the parameters, others do not.
This is the basics. There are all sorts of other things that can effect it, but the above will cover 90% of installations.
" I understand how a shoelace is tied, what I don't get is why you tie a shoe lace".
Think of a car. It has a minimum RPM of usually 800 before the engine has to switch off/stall.
Boiler is the same..,. Although the minimum varies greatly between different units for reasons we won't go into here, if only to keep Blowhardgreen in his box.
Boiler is set to 70 degrees.
When the system water reaches 70 degrees, the boiler tries to lower the amount of gas burned (its RPM) to keep the engine running that bit longer.
IF it can't, then it switches off but leaves the pump running to dissipate the heat usefully.
To prevent the boiler yoyoing on and off, there is a program built in to minimise/maximise various things like MTF, efficiency etc.
Some boilers let you tweak the parameters, others do not.
This is the basics. There are all sorts of other things that can effect it, but the above will cover 90% of installations.