check valve noise in p/s piping

Jerry Boulanger_2

Crane Technical Paper No. 410. 'Most of the difficulties encountered with check valves...have been found to be due to oversizing which results in noisy operation and premature wear of the moving parts.'

John McArthur

check valve noise

Has anyone else experienced check valve noise in primary-secondary piping? i have a system in which the spring-check valve is installed just downstream of the circulator pump (a Taco 0012) in a 2" primary header and it ratttles like crazy. I think it is from too much velocity. Any suggestions on a fix?

ScottMP

Replace the check valve.

I have had this problem before only with a radiant job.

Is it a Conbraco by chance ? Thats the ones I had problems with. Good valve, lots of brass, made really well. Chattered like hell.

Scott

Tony Conner

It's Probably...

...too big, which would mean there's not enough velocity to drive the check open, and hold it there. If a check valve is oversized, the disc will flap in the fluid flow like a flag in the wind. This is the tinkling/rattling noise you get, as the disc hits the seat. This is also the prime cause of swing checks failing, as they wear where the shaft goes though the disc. Check valves are like control valves - a pretty good rule of thumb is that the check will be one line size smaller than the pipe, if the pipe is the correct size for the flow conditions (not oversized).

hot_rod

Show us a drawing

Do you have a check in the primary loop?? I'm not clear on on the how and whys of the check location in your description.

Another option is the new batch of circ pumps with built in check. No noise, and a simple pump replacement may solve your problem.

hot rod

jose

How far???

How far away from a fitting or the circ. is the chk valve?
Usually should be 10 times the pipe size in distance (ex. 3/4 pipe = appox 7.5 inches)

Dave Stroman

What brand is it? I have that trouble with Nibco, have no problem with Watts.

Dennis Bellanti

Could Be....

The type of seat around the check. It is my understanding that mfgrs. use either Vitron or Teflon. There is a specific temperature limitation and when you exceed that temp. the seat can come loose allowing the check to flap. Watts uses both seats on different models. I think the Vitron is rated for DHW applications (up to 140). Check with the manufacturer to verify this.