How do I find out if the water hammer or knocking noise is coming from supply side or drain side?
Question:I hear knocking noise when I flush toilets and when clothes washer drains. There is no such noise when I shower or use faucets anywhere in the house. Is there a quick test I can do to determine if the noise is coming from re-pressurization of supply side? or improper venting due to clog or improper slope of drain pipe? I was thinking of flushing the toilet but holding up the floater in the water chamber. If water doesn't fill up the water chamber and I still hear knocking, would that be the drain side that's knocking? Thanks!
Answers:
This question can probably be answered simply if more information is given. Water hammer is caused by the closing of a valve. If this happened during the flushing of the toilette then it should be after the toilette has refilled. Similarly if it happens when the washer is running then it should happen during the rinse cycle when the water is being turned on and off automatically by the washing machine. Or when the washing machine stops filling.
Hot water passing through a cold pipe whether it be the drain or the water lines can cause ticking sounds due to expansion of the pipe.
More information is necessary to narrow down the exact cause of the sound.
If it is water hammer there are water hammer attenuators that can be installed on the main water line to cushion the hammer effect.
Water Hammer is because water is flowing in one direction with a pressure to provide the force. However, once a fast acting valve closes very fast, it causes the flow to come to a sudden stop and the force pushes against water that is still trying to more forward. The energy in this force must be given off in some way, and it is - in this case it is given off as kinetic energy to cause the pipes to vibrate at a specific frequency = the noise you hear.
Yes, there are valves you can install Near the device causing the water hammer. If more than one device causeing water hammer then more than one valve is required.
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