The city in which I live recently increased the water pressure to my house. All is fine except for one toilet upstairs. When this toilet is flushed, a very loud chatter occurs and lasts for about 30 seconds.
At first we thought it was air in the pipes, but it’s remained this way now over about 2 weeks. No other problems with any of the other fixtures in the house.
Sure sounds like the results of water hammer to me – check your pipework to make sure it is secured loose fitting pipes when high pressure is applied sometimes vibrate through a water pulse passing through them. Ya could always fit a pressure reducing valve to the line on the cystern as a last resort.