HR92 not firing the boiler

[Nairda]

I have just installed an Evohome system onto an S-plan heating and hot water system. I have the hot water kit installed and working properly and I have a BDR91 controlling the heating motorised valve. I have 9 zones, all but one with a single radiator and HR92 while the lounge has 2 radiators with HR92s.

Turning up the HR92s to a temperature that should cause the BDR91 to fire the boiler works as it should in every zone but one, which flatly refuses to respond. I have swapped HR92s with the same result in that zone so it clearly isn't an issue with the HR92s. I have checked the RF signal strength between the controller, HR92 and the BDR91s and all show a good healthy signal of 4 or 5.

The two BDR91s are over 300mm apart and I could separate them further but I am not convinced this is the problem as I have tried temporarily increasing the separation slightly with the added benefit of removing a wall from the signal path. The HR92, Evohome controller, and BDR91 are all within 10 metres of each other.

One other question I have is, does the HR92 communicate directly with the BDR91 or is it the controller that tells the BDR91 to turn on?

I am stumped so any suggestions would be gratefully received.

[Nairda]

Sorry for replying to my own post but the problem has been solved and it had nothing directly to do with the Evohome installation. It seems that the offending TRV was only opening to about 12-14% maximum and this was clearly below the opening required for the controller to demand heat. I changed the "Stroke" setting on the HR92 and all was well.

I have since checked all my other valves and I had one only opening to 13%, another to 26% and the rest 81% upwards. I have changed the stroke setting for the other two.