Yes it is a gate valve so that the radiatiors don't come on in the summer. I have turned the correct valve but the problem has existed since doing that. prior to that the hot water was fine.
I have a stelgrad boiler and use a summer valve. This morning I used the summer valve to use my radiators and they have only been lukewarm all day and the "hot" water from the taps is lukewarm only. Any ideas??