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Grundfos Train Chugging Sound

3564 Views 10 Replies 3 Participants Last post by  WhatRnsdownhill
Hi there,

My Grundfos pump was making a "train chugging" sound so I had someone come replace it. After about a week, it started making the sound again. I called the plumber and he told me to bleed the system to get the air out. I tried that but it still makes the sound. It's not all the time, just once in a while but it's loud and you can hear it throughout the house. I have it come on at 6am and this morning was bad.

I don't think he knows what is causing it as he won't contact me after I asked him to come back and look. Before I call someone else, does anyone know what is causing this or how maybe I can fix it myself?

This forum won't let me post links so I'll respond to my post with the video.

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sounds like the check valve or flow valve making the noise......when its making the noise tap " gently" with a wrench or small hammer to see if the sound changes or goes away...that is the piece just right of the bottom of the extrol tank, where is connects to the copper line..
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ok on your last video where you had your hand is a check valve..drain the water and open the check valve to make sure there is nothing stuck in it and it is in good shape inside, is that for domestic hot water or the heating system, it looks like a water heater from the videos?..the red circled fitting is just a copper t, not the check valve. move over about 3 that a return loop for the hot water on domestic water?
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Thanks for the replies. It is for the hot water tank.

I'll try the check value option first to see if that helps. We are on well water here, shared between 71 houses.

From here, I'll check the expansion tank.
talk to your neighbors and see if any of them are having the same issue, it could have something to do with pressure drop outside in the system, with 71 houses on a well set you have a rpz valve on the water main coming into your house?
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