Gloworm Micron 50FF- sometimes fires up but doesn't heat hot water unless CH is on

[J All]

What could be the problem? It was serviced 1 year ago.
Also sometimes even with CH and water programmed to come on it fires once, then fires again but stops after a minute or so. If I turn the electric off at the wall and reset it then switch on sometimes it will fire up but most of the time it won't. So I turn it off at the wall again several times and after a few times doing this it all works but the water still will not heat up unless the CH is on.
Another problem is one of the downstairs radiators is cold. Most of the feed in pipe gets warm but the last 12 or so inches of pipe near the radiator valve is cold. Could this problem be causing the boiler problem?
Trying to get someone to come out- leave messages, but no one wants to respond. We are getting desperate.

 

[ianmcd]

sounds like an external control problem rather than a boiler problem, if you cant get anyone have a look at British Gas fixed price repair scheme

 

[J All]

An electrician looked at the motorised valve and it is working and the water now heats up. Very strange.