The Wanderer wrote:
On Sat, 26 Aug 2006 02:35:29 +0100, diezeltruck wrote:

Hi,

The programmer that controls my central heating and hot water fails to
communicate with the boiler and the boiler is continually 'ON'

Do a google for 'S plan'. You should be able to come up with wiring
diagrams for all the common variations of heating system.

The programmer is set at 'OFF' but the boiler still fires

Wiring mistake, possibly

The RET Electronic Room Thermostat that controls the central heating
also fails to switch the boiler off even when turned fully down.

Wiring mistake, possibly

Because of this my central heating is continually 'on' and the
thermostat fails to switch do anything in controlling the room temp as
the boiler fails to switch off.

It has been suggested that I have a faulty motorised valve which is
stuck in the 'on' position.

That alone won't give rise to the symptoms you describe. If the system has
been wired properly, then the controller overides any other auxiliary
switches (like the thermostat, the aux switches on the valves) in the
circuit.


Completely WRONG. The controller does not have the power to drive the
boiler. The controller drives the thermostat and the valve motor: The
switches on the valve body control the boiler. That is why they are there.