Why am I having water hammer of water pipes banging during the night when all taps are turned off?

This could be number of issues. However, it is important that customers realise that in the situation where there is water hammer that it is a process of elimination which ultimately can end up with the result of no solution. However I would firstly be checking the following as a plumber when I attended:

These are the steps of which to follow:

Step 1. Check that there is no leaking taps, toilets, or valves on hot water heaters as this gives a cause for possible hammering throughout the night. If any of these are found to be leaking, then replace them.

Step 2. Pin or fasten any tap washers that may be left in the open position at all times; such as washing machine taps, toilet isolation taps, hot and cold water isolation taps or outside taps that may be connected to timers or irrigation. By flattening the shaft of these washers where they sit in the spindle means that the tap washer will not be jumping around when the tap is open. This is the most common form of water hammer that we do find and definitely can be a cause for the banging of pipework throughout the night.

Step 3. It can be something as simple as the irrigation system that may be on a timer where it turns on or off throughout the night. Most homes have solenoid vales connected to their irrigation which shut off very quickly and abruptly, resulting in pipes hammering. If this is the cause, change the cycle or time that the irrigating is on or off.

Step 4. If your toilet cistern has a slight drip of water going from the toilet cistern into the bowl, the ball valve within the cistern can turn on, creating a banging noise throughout the night. This leak is often undetected as it is not visible. However, we would advise putting a few drops of food colouring into the cistern which will therefore highlight a slow drip of water into the bowl. Without this food colouring it often cannot be seen. If this is the case, the flushing assembly bottom rubber will need to be changed as this is a faulty rubber where the water is bypassing and the float valve then is refilling the water throughout the night creating the shuttering of pipes.

Step 5. Once finding what the cause of the problem is, the water hammer rester can always be rested on the back tap. However in our experiences, this solution often does not work.

Step 6. A pressure limiting valve can be installed at the water meter. What this does is increases the incoming pressure to the house. It is not a solution but it often reduce the noise of water hammer.

Step 7. If you have an electric storage hot water heater, which is on a heating tariff that heats through the night, you may find that when the hot relief valve dumps water due to the hot water in the tank expanding while in the heating cycle, that you are then getting the shuttering noise of pipework also. This is a normal operational factor for storage heaters and looking at one of the above issues may assist in alleviating the hammering noise.

Step 8. We have found that water meters are hammering from the tap washer. Unfortunately customers and plumbers are not fix this as an alternative. The water authority should check it and fix it.

Step 9. Check all pipe work in the ceiling and walls and saddle support pipework where you can.

If you need assistance with any of these water hammer issues that may be occurring in the middle of the night, please call jims plumbing and we can have a licenced plumber out to you 7 days week, 24 hours a day!

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