Clanking pipes

[Doug]

I recently installed new toilets in my home and now after you flush when toilet fills and shuts off the pipes clank. I know that's caused by air in the pipes but have no idea how to get the air out. I use all the faucets in the house and don't know where the air could be.

If I reduce the flow of water to a level where the pipes don't clank then you get the sound of rushing water which is louder than the clanking. I've looked at the valve inside the tank and can't find anyway to get it to shut off more gently.

Anyone have any ideas how to deal with this?

thanks, Doug

[David Wilkinson]

Doug wrote in news: [e-mail]:

What you are describing sounds like "water hammer". It's actually caused by the lack of air in the pipes. Most water pipe systems have a tank or a small vertical section of capped pipe somewhere that is normally filled with air. When the moving water is suddenly stopped by a closing valve the water will use the air in the tank/pipe as cushion (sort of like a shock absorber) and prevent the clanking or hammering sound you hear. When the tank/pipe fills with water the cushion is gone and the hammering sound occurs.

To put air back into the tank/pipe, locate the phyically lowest spigot/faucet in your house. Turn off the water main, open the lowest spigot/faucet and allow the water to drain out. This process can be sped up a bit by opening a faucet or two that are higest in the house. When the water stops draining close all faucets/spigots and turn on the main. The tank/pipe should now be filled with air and will provide a cushion when the moving water is suddenly stopped.

[Joseph Meehan]

It may be water hammer or improperly secured pipes. In either case the most likely reason it is not showing up is your new toilet is shutting off suddenly as you suspect. You can try reducing the flow to the toilet by partly closing the shutoff valve.

Other than that, it is time to check to see the pipes are properly secured and you may want to draining all the pipes (shut off the main and open all the valves for a while (shut down the water heater when you do this).

Good Luck