Underfloor heating operates at lower
Unlike radiators, underfloor heating systems do not need
to run at high temperatures. Heat imparted to the floor is gently released across a
large area rather than the relatively small and focussed area of a radiator.
As such, UFH systems do not need to operate at such high temperatures.
This of course has its advantages. Not only is UFH less expensive to
operate, you also do away with the need for radiators and scalding that can
occur. (You also get more choice when it comes to room layout because there
are no rads!)
Dry underfloor heating systems
In a 'dry' or electric system the principle is the same.
The difference is that instead of imparting heat from water passing through a
pipe, you use the electric current passing through a special cable that heats
up as the heat source.
Control systems for underfloor heating
Of the two types of system (wet and dry)
the wet system control is far more interesting. Electric systems require
fairly simple control (basically switching on and off as heat is called
for). Wet systems certainly look complicated but in reality are quite
logical once you understand why things do what they do.
Wet control systems invariably employ a
manifold. This complex looking gadget is in fact just a means to connect
multiple pipe runs to a common heat source. Each pipe run from a manifold is
controlled by an electrically operated valve (an actuator head) which opens
and closes as the controlling room stat commands. This way the pipe run (or
zone) can put heat into a room or area as required.
In essence this is how it works....
Room gets cold > Room stat calls for heat >
Control system commands actuator on manifold to open (letting hot water down
pipe run > room reaches required temperature > room stat notifies control
system that no more heat is required > control system instructs actuator
head to close
This of course is a highly simplified
account as there are other functions at work such as boiler control,
temperature regulation, circulation etc. But it does at least give you an
insight to the system control.