Cor 20 with a plumbing Hum

justingraham · Jun 25, 2018

So I have a cor 20 from the first shipment.

And I want to say after two months I heard this Hum and I placed it to my cor plumbing.

Ever since that point the Hum has never went away

Yesterday I swapped out my sump and when I did I put my old vectra in its place to see if I needed to replace my plumbing but the hum went away. After I was done cleaning my Cor I put it back in and the hum was even louder. Loud enough where my girlfriend now hears it.

My plumbing is like so
4 feet of 1.25 to a 90 1.25 then one more foot of 1.25 then it gets down graded to a 1 inch flow meter then thru a 3/4 sea swirl.

Besides switching out to my other m1 how do I make the hum go away?

Some photos of the pump and plumbing

justingraham · Jun 25, 2018

To the best of my knowledge The hum is coming from the plumbing not the pump

User1 · Jun 25, 2018

I tend to agree with @justingraham on this - I've read some threads on other forums including Neptune's with this issue and it was related to plumbing. I have a pair of Cor 15's (obviously not a 20) from the first batch and have zero issues. I seem to recall a thread here on this board in which plumbing was directly related to the noise. If not a hum then related to cavitation.

ca1ore · Jun 25, 2018

You've got to figure out what's causing the hum. PVC doesn't inherently hum

, but it can transmit hum from the pump. Try ramping down the COR to see if the problem goes away. That you run native 1 1/4" out of the pump is a good thing. You've got enough back pressure on the output of the pump that I'd not think cavitation would be an issue ..... but you never know. Try putting the pump on some kind vibration absorbing pad.

justingraham · Jun 25, 2018

The pump isn’t vibrating it’s the pipe that’s making the noise
I will try ramping it down but it’s already at 70%

Mark Gray · Jun 25, 2018

I have 2 Cor 15s they are dead silent. Can you maybe get some PVC support brackets and try sort of tying them down

justingraham · Jun 25, 2018

Mark Gray said:
I have 2 Cor 15s they are dead silent. Can you maybe get some PVC support brackets and try sort of tying them down

Thanks for ur input

It’s really hard to explain the pipe is secure the pump is not moving it’s not a vibrating noise it’s a hum. Like from the water against the inside of the pipe.

It’s kinda like the high pitch of a halide bulb if u ever heard that but at a lower decibel

Mark Gray · Jun 25, 2018

justingraham said:
Thanks for ur input

It’s really hard to explain the pipe is secure the pump is not moving it’s not a vibrating noise it’s a hum. Like from the water against the inside of the pipe.

It’s kinda like the high pitch of a halide bulb if u ever heard that but at a lower decibel

Oh I understand not sure if this will work but it might, if you have any unions brock it there get some PVC glue and a small peice of scrap PVC glue it to the inside of the pipe, I believe this should change it and hopefully make it go away Good luck

ca1ore · Jun 25, 2018

All hums are a consequence of vibrations (that's how an audio speaker works). The pitch of the hum is a function of the frequency of the vibration. It could be coming from the pump or it could be coming from turbulence of water inside the pipe. That it is a high pitched hum is odd, though changing the speed of the pump should affect it.

justingraham · Jun 25, 2018

Mark Gray said:
Oh I understand not sure if this will work but it might, if you have any unions brock it there get some PVC glue and a small peice of scrap PVC glue it to the inside of the pipe, I believe this should change it and hopefully make it go away Good luck

What?? U lost me

ca1ore said:
All hums are a consequence of vibrations (that's how an audio speaker works). The pitch of the hum is a function of the frequency of the vibration. It could be coming from the pump or it could be coming from turbulence of water inside the pipe. That it is a high pitched hum is odd, though changing the speed of the pump should affect it.

That is true I have to get home and lower it but like I said I’m at 70 percent I don’t think I’ll ever run it lower then that

So if it does get quiet with lowering the speed then what?

Mark Gray · Jun 25, 2018

Double post

Mark Gray · Jun 25, 2018

Triple Pose lol

Mark Gray · Jun 25, 2018

justingraham said:
What?? U lost me

That is true I have to get home and lower it but like I said I’m at 70 percent I don’t think I’ll ever run it lower then that

So if it does get quiet with lowering the speed then what?

What my thoughts were was creating a ridge inside your plumbing not a large ridge but it might change the vibration enough to make it go away

Dr RBG · Jun 26, 2018

would putting a section of silicone tubing in series with the hard PVC act as an isolator of sorts and dampen the hum? Just a guess. Any thoughts on this?

Mark Gray · Jun 26, 2018

Dr RBG said:
would putting a section of silicone tubing in series with the hard PVC act as an isolator of sorts and dampen the hum? Just a guess. Any thoughts on this?

Yes might work