Your boiler's timer or schedule has lost track of its settings, which usually means the clock or heating programme needs resetting rather than a serious fault with the heating itself.

DIY fix possible

Check the time and date on the boiler's control display and correct them if they are wrong.Check your heating and hot water programme settings and reset them to your usual times if they look incorrect or have changed.Switch the boiler off at its electrical supply, wait 30 seconds, then switch it back on and see whether code 449 clears.If the code returns within a few days or the boiler stops heating or providing hot water, stop trying to fix it and contact a Gas Safe registered engineer.