Problem with hr92 radiator valve resetting itself

[Clarky232]

Hi all

New to evohome and the forum this is my problem we have a new installed central heating system with new evohome system we have 8 hr92 valves 7 work fine but one keeps turning temperature down to 5 degrees whilst the others stay at 20 degrees which is what there all set to any ideas

Cheers paul

[Richard]

Could be the 'window open' function... Is there a window symbol on this zone on the evohome Controller when it does this?

[IKnowNothing]

That had me foxed for quite a while. My rad was near my conservatory door, so that when I opened it the temperature of that valve dropped too quickly causing the window open alarm to shut the valve down.
Initially I couldn't believe it, thinking that the only window open alarm was the physical switch which can be connected to the valve body.
I have disabled this feature on all my valves.