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'

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?

Either.
They are wired 'or'

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.


That one (in an Andy voice)

Will I have to drain the system?

Maybe. Take the actuatoir off and try wiggling the valve stem

Sometimes swarf or scale causes them to jam. If you can free it up
enough the actuator motor may be able to move it again, or if its burnt
out, new actuator.


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!!


Certainly remove it and check the spindle moves. Mine did this and only
needed a new motorised bit.

If you disconnect the actuator switch contacts temporarily, at least the
boiler won;t come on all the time.


What does anyone think?

please advise

Cheers

Diezel