I wonder if this is some kind of balancing valve, perhaps if the rad circuit was extended with extra rads after being built?
does it have a wheel-shaped head rather than a T-shaped head?
some photos of the pipe layout around this valve may help (though if you are getting a plumber in he will probably sort it)
I have my bathroom radiator on a special loop tapped off the flow and return in front of the 3-port valve, and this has to be specially balanced to stop it stealing all the flow.
does it have a wheel-shaped head rather than a T-shaped head?
some photos of the pipe layout around this valve may help (though if you are getting a plumber in he will probably sort it)
I have my bathroom radiator on a special loop tapped off the flow and return in front of the 3-port valve, and this has to be specially balanced to stop it stealing all the flow.