Boiler power problem

TheGreenFrog

I am trying to work out what has caused the power to my boiler to fail. It is oil fired. The problem appears to be from the frost thermostat but I don't know why that should be. Picture attached showing the wiring. Mains power comes into fused switch on left - there is power to the switch and the fuse works, as does the switch. There is also power (presumably flowing from) the frost thermostat through the T&E cable leading from the top of the thermostat. The white cable leading out of the top of the thermostat goes to the water pump on the heating system, and the cable leading out of the bottom goes to the boiler. There is no power to the boiler. I think the problem must be with the thermostat but I don't know why - the thermostat was replaced a couple of years ago because it had failed - but in that case the boiler was running constantly. Any pointers gratefully received.

Edit: I tried tripping the thermostat by increasing the temperature it was set to. The boiler fired up. I think must be problem with the zone valve, not the thermostat.

WIAWSNB

You say there is no power going to the boiler? What do you mean by this? Does it have a 'power on' indicator?

Picture of front panel, please.

That frost 'stat appears to be working ok - you turn it up, presumably to ambient temp, and the boiler comes on. That also shows that the boiler is working - it is receiving power.

So, if the boiler is working, and the frost stat is working, then it is surely the other controls wot are not? Ie, the 'timer' - what type? - and the room 'stat - ditto?

TheGreenFrog

https://forums.moneysavingexpert.com/discussion/comment/81922663#Comment_81922663

Yes you are right. It was one of the other controls. Since Iran etc I have restricted boiler use to hot water and then only using the one hour boost function on the timer. It turns out that the boost function, although lighting up on the timer, is not doing what it should be. Central heating works fine (when I switched it on for 5 seconds) and hot water works if I put timer to constantly on function. So problem solved sort of.