The question is more, is the boiler delivering the specified ammount of hot water......
Get it serviced, and ask your technician to check to flow rate & temp. of the water, what your looking for will always be specified in the manual as temp. increase and ltrs per minute.
Usually the temp will be specified as a detla value, but it is normally 35deg increase from the inlet water temp. then ltrs per min after that
T
April 2008