If you're still not getting the comforting warmth you expect from your boiler, look at the boiler pressure. If you notice the water from your hot taps is running at a lower flow rate than usual, you may have low water pressure.
Look at the gauge on the front of your boiler. It should show a reading of between 1 and 2. Anything below one bar is low, whilst anything above 2.75 is high.