Noisy circulators

Adirondacker

We have a hydronic radiant floor heating system (new construction, 5 zones). When the system calls for heat and the circulators come on, the house sounds like a boiler factory. The basement where the boiler is located is quiet, but the noise in the living space is unbearable.
The system uses PEX tubing but has long runs of copper pipe between zones. All of the circulators are hard-mounted to a large plywood panel. Any ideas on where the noise is coming from and how to fix?

Big Ed

Circulator

What brand circulator and what porsition where they installed ? Take and post pictures will help..

Constantin

Are your pumps pumping away from the boiler?

A picture would certainly help.

Given that the noise is not in the basement, but upstairs, makes me suspect low pressure in the circuits upstairs. That in turn can lead to bubbles forming and collapsing as air comes out of/re-enters solution and this sort of cavitation is very noisy. Putting pumps on the return (i.e. into the boiler) can make the problem worse because they're effectively creating a vacuum in the piping upstairs.

What about the system pressure? We had cavitation and other issues until we increased the system pressure from 12 to 20 psi at the behest of Grundfos, the pump manufacturer. The thinking being that there has to be at least some pressure on the 3rd floor for air not to come out of solution, even when pumping away. At 20 psi, the system is running virtually silent.

How well are the pipes upstairs supported? Even minute pressure variations can cause pipes to vibrate and "sing". Perhaps not audibly in the basement where they are mounted securely to the wall, but elsewhere they may have enough flex to make noise. Securing the piping and/or removing/remediating the offending source of vibration would do the trick, I imagine.

There are so many things that can cause vibration and noise... and water/pipe is a great way to transmit it, unfortunately. From this homeowner to you, best of luck finding and eliminating the source. I'm sure the pros here may have dealt with far more causes than I have listed above, so I look forward to hearing from them also.

Weezbo

could be a numer of independent variables.

expanding copper pipe without swing arms, air in the system , wrong size circs, wrong pumping stradgey, too many pumps, no plastic squeakers, mounting brackets non existent, no harmonic dampening at the boiler pump panel.. just to name a few.

ALH_4

maybe

It sounds as if you may have something stuck in the pump, or the impeller may be contacting the housing for some reason. The walls and floors can amplify this sound so that it is louder in the living space than if you are standing next to the circulators. I have seen systems with 26-64's silent unless you put your ear to the pump, but clearly audible when standing in the living room.

Does the sound continue until the system shuts off or does it occur only for a short while when the thermostat calls?

-Andrew