"Martin Evans" wrote in message
...
hot water and radiators are all hot


So the valves are both open? Have you taken a look into the wiring centre
and tested to see whether the motor "open" signals are present on the wiring
to the valve motors (brown wires in the multicore flexibles)
Just to help a little a standard s-plan valve head uses brown (or in the
case of Danfoss valves brown&white) as the motor supply, blue as motor
neutral, green&yellow as earth, grey and orange are connected to the limit
switch which closes contact when the valve is open. A few such as Honeywell
also have a white wire which is used with an alternative changeover contact
limit switch for use in a c-plan system.
If the brown wires are live then the problem will be outside the valve motor
heads and the programmer needs more investigation always assuming that there
aren't any external influences such as frost stats.