Radiator heating dilema

[Hugh Jaleak]

There's plenty of X400 in there, I doubt filling the system with neat X400 would make the slightest difference. Manifold may be blocked but that would only affect the rads, not the hot water.

Just to rule them out, are both motorised valves open? Be pure coincidence if both have failed but not impossible. If you open manually on the levers, should be some resistance as you are pushing against a spring. If that still doesnt help, I would remove one of the head and just check the spindle is turning and actually opening the valve. If the motor is working as it should then boiler and pump will be energised, but if the water cant get past the valve(s) (as it's broken/stuck shut) then system wont work....

 

[Meggalar]

Ok, i'll not go for another bottle of x400.
I've looked at the motorised valves and they are the 2 way Honeywell type on a straight run of pipe.
There doesn't seem to be any spring resistance at all on either of them when sliding the switch towards the catch. I'm sure thinking about it there used to be when i've tried that previously.
Is it possible that they could be stuck and only letting some of the water past them? That seems to make sense.
I've not had the courage to take the cover off them yet.
Just so i'm clear on the motorised valve, are they open or shut when pushed towards the end where the catch/hook bit is?
Thanks again

 

[Meggalar]

Just a bit more information.
Noticed that the hot water wasn't all that hot any more. So just tried the HW heating on its own and the HW is now hotter than its been for a while.
The CH & HW are usually set to come on at the same time.
Thanks