Boiler won't stop running!

[shave]

Equipment :
Grant Vortex condensing boiler
Hot water on Danfoss hard wired programmer [set to OFF!]
2 x TP5000 RF termostats
1 x RX2C Danfoss heating receiver

Situation :
Paired thermostats with no difficulty. When thermostats set to demand heat, the receiver shows a red light against the appropriate CH 1/2.

Problem :
But the boiler just doesn't stop!

Attempted solutions :
It just keeps on chugging. I've set the HW to OFF to eliminate this as a demand. I've reset the thermostats and cut the power to the controller and re-commissioned it, no dice. I've let it run for a couple of hours in case it figured it out on its own, no joy. I've just turned off the boiler and will let the thermostats carry on overnight in the hope they haven't already told the controller to 'stop'. Up till now, as soon as I switch on the boiler it fires up and starts turning the place into a sauna.

Help:
Any ideas folks?

My next thought so were to isolate and dismantle the controller and then scratch my head.....

 

[picasso]

What motorised valves are on your system ?

 

[oilboffin]

Motorised valve sticking

 

[shave]

The valves are Danfoss HTG. I've pulled the panel off the wall where it hides the pipe work. The vales appear to be functioning as there's no HW to the central heating, just a couple of hot rads in the bathroom, probably plumbed into the HW circuit I suspect. The HW seems to be on full demand so now it's the HW Controller which is the main suspect. Going for a full reset on that now....

I imagine that's what is making a demand on the boiler... ?

 

[shave]

Now I've discovered that there's actually no hot water to the taps, just hot rads in the bathroom. Crazy! Ahhhhhhhhhh!

 

[JohnD]

your first post gives me the impression this is a newly installed system. Is it?

Did it ever work properly?

 

[dilalio]

If new - wiring fault. Boiler getting demand from somewhere - powered switched live at pcb perhaps?

 

[shave]

Just moved in, never run the system as not needed it. Thought it wise to take a look before the winter comes.... I suspect now that the proverbial black box is causing a heating demand.

The system is a bit weird. Two thermostats, one for upstairs and one downstairs. And a HW circuit which seems to operate the rads in the bathroom too....

I suspect what I need is a heating engineer to service it , take a look, give me some advice, and clean the nozzle!