It's more likely that it's functioning as the bypass and doesn't come on in the summer. Both the motorised valves have been replaced over the last 20 years so it's possible there was a summer when the valve was faulty which has made me think it's stays hot.
It's more likely that it's functioning as the bypass and doesn't come on in the summer. Both the motorised valves have been replaced over the last 20 years so it's possible there was a summer when the valve was faulty which has made me think it's stays hot.