|
These pages
are designed for householders who already
have Honeywell heating controls or are selecting the
best controls for their home.
To get the
best efficiency (hence lowest running cost) from a heating
system, all components need to be considered together:
Is the
house well insulated?
Is the boiler efficient?
Is the system well controlled?
Any system
that has one of these elements missing will cost much more to
run and will produce unnecessary emissions.
We can
explain a system relatively simply by thinking of the hot
water supply and heating supply separately.
The heating
from radiators is normally achieved by pumping water, heated
in the boiler, through them. Water leaves the boiler hot in
the 'flow' pipes and comes back cooler in the 'return' pipes.
Systems
used to have the hot water cylinder situated right above the
boiler so that a pump was not needed in the hot water supply
circuit. Hot water from the boiler would rise gently up a
large diameter pipe to the cylinder and gradually heat the
water stored inside. This is called a Gravity
Hot Water (GHW) system. (C
Plan)
More modern
systems are plumbed so that the pump pushes water through the
heating coil inside the cylinder. When both the heating and
the hot water circuits are supplied with pumped hot water from
the boiler, the system is referred to as Fully
Pumped (FP).
(One
further development in recent years has been the Combination
Boiler or 'combi' - which does away with the need for stored
hot water by providing hot water directly from the boiler.
Care must be taken when selecting one of these to ensure that
there will be enough hot water available). (Combi)
Having
established what sort of heating system you have, you can
decide what controls you need. The Government’s Building
Regulations, the Building Research Establishment (BRE) and the
industry’s “best practices” all demand that the minimum
standard of controls require a boiler interlock to prevent the boiler from firing when there is no need for it. For a
system with stored hot water, controls are required to do
this, normally a timer, a thermostat for both heating and hot
water and motorised valve(s). (S
Plan) (Y
Plan)
For a combi
boiler, an interlock is still required, but it will consist of
a room thermostat of some sort. (CM
range)
Organisations
concerned with efficient home heating have worked together to
produce a document entitled Central Heating
System Specification (CheSS)
to help with the selection of controls. (Chess)
|
