Rattling Spring Check (again)

_ray_

So, I know this has been asked and answered in the same way a number of times, but, I'm still wondering on one thing...



Many have stated that the rattling is often due to wrong size valve and the rule of thumb suggestion is that the valve should be one pipe size smaller.



This makes sense to me if the rattling is occurring when there is low flow going through the valve. However, I have the opposite problem. I hear the rattling only as more zones are calling. So, am I misunderstanding the sizing comments and this is my problem also, or, do I have a bad valve? Any thoughts?



Thanks again everyone...

hot_rod

flow rate

dio you have a means to confirm the flow rate? How about air in the system, does the circ run nice and quiet? How close to the circ is the check mounted? On the discharge side?

_ray_

using a bumblebee

I have a bumblebee set with with a 20 degree delta T, so the rate varies to achieve this depending on how many zones are calling. Its not the quietest circ though, but I think that is the circ itself rather than air (i've read about others not enjoying the volume of that one). The circ is on the supply manifold, the check is on the return.



thanks!

hot_rod

what type of check valve

most check valves built for hydronic use have a very low "pop" pressure. i believe the checks used in most circs pop at about 1/2 psi. They also have a soft seat and are virtually silent when they close.



It sounds like you might have a swing check? Or a check designed for a well pump perhaps?



Here are some of the checks that are installed in circ pumps. Probably built by Neoperl. You can buy unions with these built in, also. They have a light spring, a cone shaped check, and a soft plastic/ o-ring seat seal.



The ones used for solar are black plastic and have a higher temperature rating, these are fine for hydronics.