Circulator Pump - Making noise

[ali2]

Hey everyone, first time posting here, so I would appreciate any help. We have a water heater and a Grundfos pump circulator. The circulator was old and died, so we got a new one. Upon installing it, it has been making a low humming/buzzing sound and I do not know how to fix it. It sounds like it may be coming from the water heater, but I am not sure. When I unplugged the pump, the sound is turned off, so I know that is the source. I read it could be air in the system, so I flushed the water heater (I think properly) and it is still making noise. Any advice would be appreciated. The pump is a Grundfos UP15-29SU

 

[havasu]

Pull the pump and check for sediment stopping the pump from working.

 

[ali2]

We checked for sediment and there was no issue there. The pump itself is working perfectly, its just making that sound. It kind of sounds like the sound may be coming from the water heater too, I am not sure.

 

[havasu]

Maybe a bad bearing on the pump?

 

[Twowaxhack]

Could be s bad pump, new or not.

 

[ali2]

This is the second pump we got from them. The 1st one we got was extremely loud, which they said may be a bearing issue. They sent us a replacement, which isnt nearly as loud. The thing is at first it was quiet. About 2 hours later I started my dishwasher and it started to make noise after that.

 

[Twowaxhack]

You might have a bad check valve or a valve in general making the noise then. Or it could be another bad pump.

 

[Jeff Handy]

Did you drain sediment from the heater before installing new pumps?

 

[Jeff Handy]

Never mind, I missed where you already checked for sediment.
Unless you did a poor job flushing it.

 

[Jeff Handy]

If heater is more than about 8 years old, there could be minerals or rust on the bottom, vibrating when the pump is running.
Or maybe the draft diverter is vibrating.

 

[Twowaxhack]

If heater is more than about 8 years old, there could be minerals or rust on the bottom, vibrating when the pump is running.
Or maybe the draft diverter is vibrating.

I believe the noise stops when he turns the pump off.

 

[Jeff Handy]

Yes, I got that.
I am saying the pump or circulating water can be vibrating the areas I mentioned.
When the pump is running, just an idea.