I have a weil mclain boiler that makes a very annoying clicking sound that comes in and out. it is VERY irritating, and is most noticable at night when there is little background noise. it seems to be coming from the taco valve zone head. I can actually feel it ticking when I touch it as it is making the sound. if I adjust it by twisting the head slightly it subsides for a short while, but always returns half way through the night. it is driving my nuts!!

can anyone tell me if it is just a bad zone head or if there is a way to stop it before I take a baseball bat to it??

 

I'm not familiar with Taco zone valves but if the noise changes when you "twist" the valve head then most likely that is where the problem lies.