can any one help? just replaced primatic cylinder. 900 x 450 with 27 inch immersson. straight swap no new pipe work. but for some reason the water storage tank seems to keep filling up. to the point it is over flowing.?it seems to come up from the cold feed to the cylinder how this poss is it a faulty cylinder? just had new bathroom suite installed could this have any problems to do with it ? really need help on this one as cant have water on due to it keeps fill tank up.