Help! This noise is driving us crazy.

[jb4e_seattle]

Hi,
I just stumbled on this great community and I’m hoping someone more knowledgeable than me can help.

Our house has a utility closet under the stairs with a combo-boiler and a small electric water heater with a pump to circulate hot water to the taps. The circulation loop was initially plumbed in copper, but we had 2 pinhole leaks over the course of a year, including one in the ceiling of the closet that required us to rip out the drywall.

The plumbing company we hired recommended we replace the copper pipes with PEX. We did this, but with that change, the pump/water running through the pipes has gotten louder.

I’ve had them back out to look at it, and they say everything is normal, and it admittedly isn’t all *that* bad, but it is definitely louder than it was before, and it drives us crazy while we sit in the living room that is adjacent to the utility closet.

The bulk of the noise seems to be transmitted through the joists the PEX runs through, which are supporting the subfloor of the stair landing above the room. There is also no insulation between the PEX and the subfloor.

Examining the situation, my first thought is that I should move the horizontal run down below the joists into the room itself, then insulate and drywall the ceiling again to isolate the noise.

My questions:
1. Is moving the horizontal run below the joists a bad idea for any reason? Are there other solutions you’d recommend?
2. Can I do this myself? I have never worked with PEX, but am fairly handy. I am not concerned about making the connections successfully, but I’m wondering what I need to do in terms of bleeding the system afterwards, etc. to make sure I don’t screw anything up.
3. If I did this, there would only be a couple inches of PEX after the outlet of the circulation pump before a 90. The pump documentation states “If possible, do not install elbows, branch tees, and similar fittings just before or after the pump.” How bad is this? Would it help to move the pump down a few inches to increase the length before the 90?

Thank you in advance!

-Jacob

 

[Breplum]

The recirculation system should be 3/4" PEX
That elbow right after the pump could be causative.
We always want to have bleeder tee with valves and isolation valves on a pump on both sides to bleed off air.
Pumps need to be supported by something other than dangling off PEX

 

[Sponsor]

 

[jb4e_seattle]

The recirculation system should be 3/4" PEX
That elbow right after the pump could be causative.
We always want to have bleeder tee with valves and isolation valves on a pump on both sides to bleed off air.
Pumps need to be supported by something other than dangling off PEX

Thank you @Breplum!

Do you think replacing the elbow with a bend would reduce noise? I could drop the pump about 6" and get that done.

The pump was previously supported by copper pipe from the top. I will figure out a way to get it some support now that we have PEX there.

The 1/2" -> 3/4" change is probably more than we can handle right now, and the system seems to work with sufficient flow currently.

Thank you again!