Daikin Altherma Air Source Heat Pump EHBH08CB3V3

We had a power cut the other day and now our hot water is very much reduced in temperature, just won't get up to where it was - unit set to 55ºC

Checked everything on the unit and all seems normal, no error messages, all settings are as they were.

Initially the outside unit just didn't run at all so I turned the system off, left it for a while and then back on and now at least everything seems normal but the water is still not as hot as it was.

Any suggestions would be most appreciated.

Thank you.