Hi,

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

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

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

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.

I assume that the motorised valve operating the central heating may be faulty.

There seems to be 2 motorised valves beside my water tank:-

1 - Synchron HPA2 Actuator/HPV26 valve(plastic box/white cover)
2 - Synchron 272848 Honeywell Motorised valve(metal box)

But which valve of the two is faulty?

1 is situated just above and in line with the pump and feeds into the top of the cylinder tank

2 is situated off of the main pump and and then travels down to the ground floor.

I guess that 2 is the one that controls the central heating?

All the wires that serve both valves go into a junction box so it is easy to isolate each valve but which one?

Will changing just the actuator resolve the problem because having had both actuators off each valve appears to turn except that 2 valve is what I could say a little stiff and jerky.

Will I have to drain the system?

There appears to be alot of 'stop taps' above and below each valve which sould facilitate removing of the valve.

I am tempted to just change the actuator!!

What does anyone think?

please advise

Cheers

Diezel