On Oct 24, 3:48*pm, The Natural Philosopher
wrote:
NT wrote:
On Oct 24, 11:39 am, fred wrote:
In article
, NT
writesOn Oct 23, 1:07 pm, fred wrote:

The whole object is to avoid heating the rest of the house.
I think the object is to pick the cheapest to run system
I'm sure the o/p now has enough information to make his choice.

Why would
this waste heat hang around until the evening? I expect the energy will
have dispersed to the ether long before then.
If you heat a house to 20 in the morning, and leave the system off
till 6pm, a good 80% of that heat is still retained indoors by then.
If you've ever had a home heated by storage heaters you'd know that
isn't the case.

I know its usually the case from many examples of heating being left
off for hours.

Either way I don't see that as the main issue, I view it as bad practice
to design a system that will repeatedly short cycle a boiler. I designed
my system for a long slow burn to avoid the thermal stresses that
repeated cycling inevitably brings and I hope to reap the benefits of
this in a longer system life.
Is thermal cycling a major failure mode in boilers? I didnt think it
was.
The more you cycle something the shorter it lasts, cars, electronics,
whatever. If the ignition circuit of the boiler lasts for say a million
hits then the service life will be reduced by repeated over-cycling.

there is no such blanket rule, only some things die from cycling,
primarily lightbulbs.

ANYTHING mechanical will supper strain on joints from thermal cycling,

nonsense. Stuch strain only occurs where the design doesnt avoid it.

up to and including integrated circuits.

Remember the boiler itself will lose a lot of heat to the room its in.

you dont say