Rob R. wrote:If the check is on the same zone that is running, it is probably just worn. You can try changing the harmonics by adjusting that valve.
Hi Rob R., not trying to steal this thread but, this is the first time I've read about check valve rattle on this site. I have check valves in each one of my secondary circulators. They've rattled from day one (new). Only the zone calling for heat would rattle. It does not rattle other zones. From what you're saying, the check valve has too much freedom, which is why it rattles. Closing the ball valve a little would put more constant / steady preasure on the check valve, elimitating the rattle. Am I thinking correctly? I answered my own question: I just walked down cellar and tried closing the ball valves some. At about 45* closed, the rattle quieted down, but is still there. I also noticed a new noise of the circulator working harder. So, I openned the ball valves again. The only room I hear rattle is the office, just above the circulators. Before putting check valves in the circulators, the entire system was whisper quiet. Oliver