
So all the water slowly rises a bit at a time?
Why when im using the hot water it can quickly become cold?
When the tap is off, the water is constantly circulating.
When you turn on the water, the water you take out is instantly replaced by new unheated water from the supply lines... Which, especially in the winter, can drop the temp very quickly - or even, if the pipes are set up just wrong feed straight into the outlet pipe to your house...