John Rumm - VRC 470F more.

[Harry Bloomfield]

Hi John - still doing battle royal with this and no progress, no conclusion at all..

I wonder if you might do me small favour?

Check your The VRC 470F, going into Installer Level> System> Control Modules -List, mine shows - Display 1.24; Receiver 1.20; VR61 1.15; Heat Generator 7.02...

It seems a little odd that mine shows VR61 when it is supposed to be a VR65 Controller. It came in a VR65 box, the instructions are marked VR65, the layout is identical to a VR65 and a VR61 is a very different animal entirely, but I wonder if it might have been flashed with the wrong firmware at the factory or something? Or perhaps all of these controllers report as VR61?

[John Rumm]

I get:

Display 1.28 VR61 2.11 VR81 2.02 (the stat in my upstairs zone) Heat Generator 2.05

Short answer, dunno...

It could just be that the 470 is old enough, that is the highest model of wiring centre it recognises. Depends on whether that list is a raw display of what the kit is telling it, or whether its got a bit of "sanity" filtering in there first...

[Harry Bloomfield]

John Rumm laid this down on his screen :

Thanks, is your controller actually a VR61?

[John Rumm]

Yup.

[John Rumm]

... and in case it matters, driver three 2 port valves: 2 heating zones and one DHW.

[Harry Bloomfield]

So your system is correctly reporting the Control Unit..

I have once again emailed Vaillant, telling them my latest findings and invited them to suggest a way forward.

Today I tried running it with no call for CH, time allowing HW and a

70C call for HW. [This] Valve moved to HW, boiler showed a call for HW, boiler did its quick purge before igniting, then showed its anti-cycling symbol, then valve may move the CH and just looped around from (this).

Turn the desired room temperature up and it left the valve in the HW position and the boiler fired up and diverted some heat into the cylinder. Because it though it was heating the CH, the boiler's output temperature was too low to add much heat.

I have tried 2x actuators, then a Sunvic 2701 (spring return) by manually turning the actual water valve to the positions indicated by the 2701 - to avoid having to swap the incompatible water valve. All produced the same HW problem.

My conclusion had got to be that the VR65 was faulty straight out of the box.

[John Rumm]

With your setup, it seems to be implicated on both the control side and on the demand sensing, since both the valve and the NTC/Stat are connected to it. (on my VR61, the valve is controlled by the VR61, but the NTC is connected directly to the boiler)