Air in the pipes causws a chunk-chunk-chunk sound when toilets are flushed

We’ve a 40 your house. Air in the pipes causes a chunk-chunk-chunk sound when the toilets are flushed.

There are procedures on line for turning off the main water at the street, opening all the faucets, turning on the water main and then closing the faucets in a certain order to flush out the air.*** These procedures work!***

But - a few months later the sounds return.

Short of paying a professional is there someway to find out how the air gets into the pipes and prevent a recurrence?

you want some air caught in some Water Hammer Arrestors to prevent the noise. if you don’t have some then have some installed.

If you open a wall behind the shut-off valve (sink, lavy, tub, whatever), you will see a stub of pipe which extends above the valve, but then is capped, with no further connections.

This is the Hammer trap.

What is happening:
When the valve (including the flush valve) opens, water starts rushing through it. When it closes, the water rams forcefully into the valve. This is the noise.

That length of empty pipe (15-18"/ .4m) provides a run-out for that water - it compresses the air in the stub. The water is now pushing against (compressed) air, and stops. No noise.

The fix is to create an extension of pipe above the valve.

As plumbing jobs go, it is about the easiest job which requires opening a wall and adding fittings and pipe.

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Screw the code - this machine is flaking out
Where x is the valve
Just extent UPWARDS the supply 15-18" above valve.

Those will work for a while, but they do eventually get water-logged and you’ll have to shut off the water and drain them to re-charge them with air.

It sounds like you are getting air in your water lines because you are at the high end of a distribution system and/or near the end of the a water main in a distribution system.

The sound you are hearing is called water hammer. What is likely happening is that flowing water when abruptly halted, “bounces” around in your pipes because there is a “pillow” of air in your pipes.

You could get an air release valve, but the problem is really not yours, it is the water systems.

Or, I may be out to lunch.

Um, I stand by my statements and advice.
See building code for details
Installed those run-outs in 1982, never needed maintenance of any kind, still going strong when I sold the place in 08.

p.s. - you WANT air in the system - those run-outs need to be filled with air - air can compress, absorbing the impact of the rushing water suddenly stopping.

p.p.s. - even if you could get all the air out, as soon as you sut off the main to replace a valve, it would be back.

Let me know when you see a plumber bleeding a house to get the air out :rolleyes:

I probably described the problem wrongly in my OP. I wrote " Air in the pipes causes a chunk-chunk-chunk sound when the toilets are flushed." I should have written * **something *causes a chunk-chunk-chunk sound when the toilets are flushed.

The chunk-chunk-chunk starts when toilet reservoir start to fill and the chunk-chunk-chunk stops when the reservoir is full. Other places, faucets, dishwasher etc. do not make the noise.

does the chunk-chunk-chunk sound seem to come from in the walls? id so then likely a water hammer.

does the chunk-chunk-chunk sound come from inside the toilet tank? lift the tank lid and then flush.

This does not sound like water hammer. Pull the lid off the toilet and flush and listen. It could be the fill valve in the toilet making the noise. Cheap and easy to fix.

Getting back to water hammer for a second the source can also be a failed pressure regulator allowing too much water pressure in the system. Replacing a pressure is a whole lot easier than opening a wall IMHO.

If the sound is from within the tank, let it fill 1/2 way (or so) then grab the float and hold. That should stop the filling, and the noise. As you slowly lower the float listen to the stem on which the float’s arm mounts - I’ve never heard one go bad, but it is likely the shut-off controlled by the float. Only it and the flapper are moving.

Plumbers use other faucets to bleed the air from plumbing after having done work. When I ran water distribution systems we always bled air from the system using fire hydrants after replacing main line valves. Air will otherwise usually clear itself from water systems though toilets, faucets, and the like. When you have high points in water systems you have to add flushing valves in order to bleed air that will otherwise collect there. You really don’t want air in your water system.

Study shows this a common query on internet plumbing and self help sites.

It is usually called “pipe clatter” and is distinct from ‘hammer’ and is attributed to air in the pipes.

A temporary solution is bleeding the pipes by turning off the water at the source, opening all faucets, turning the water back on at the source, closing all faucets in high to low sequence.

No internet site I have found suggests a permanent solution except paying for a plumber.

Does the clatter harm the plumbing or is it just harmless noise?