The hot water tap in my kitchen whistles quite loudly when it is in a certain pressure range -- at very low and high pressures it is fine, but within the sweet spot it whistles away.
It also seems to have a mind of its own, where it will turn itself anti/counter-clockwise (to higher pressure) without me touching it. It can become quite annoying (and dangerous!) when washing dishes as suddenly the water will become hotter because the hot water tap has turned itself to a higher pressure.
The cold water tap is unaffected by this.
I recently had my hot water system replaced because it was leaking, but this didn't make a lot of difference to the behaviour.
Other than getting a plumber out, is there any way I can figure out why this is happening?