I had a solar geyers (water tank) for 8 years and it started leaking and needed replacing. The old tank was fibreglass (?) and worked excellently.

Sine day one of the new stainless steel tank I have had problems. The major problem is a loud water hammer that is very disturbing. The installer has checked twice and says there is nothing wrong.

I have also noticed the water is not as hot as the previous tank and the pressure release value appears to let out more water (but difficult to say that is definitely so)

The installer says these item are because it is mid winter and it should improve when summer is here. (I do not remember this being an issue the last 8 winters)

Any suggestions ?