Been helping out at Dad’s house and noticed hot water was very hot. Had new thermostat fitted now set at 50 but water still very hot, when I turn stat it clicks around 70-80. Tank is about 20 years old.

How is the water heated? Is it an immersion with a stat on the immersion heater or via oil/gas (indirect cylinder) with a tank stat. attached?
Rich.

Immersion with stat on it, gas boiler. Ta

I think there will be a thermostat that links to the boiler that you need to alter as this is what normally heats the water – you’ve probably altered the electric immersion thermostat.