Boiler stops then restarts for about a minute

Hi, we have a boilrmate 2000 coupled to a Potterton Suprima 40. When the store temperature drops below the threshold the BM calls for the boiler to start and top it up to the upper set temperature. The boiler might run for 15-20 minutes doing this. The store must reach its desired temperature and shuts the boiler down. Instead of staying off for a good time, the boiler restarts after a few seconds and then runs for another minute before shutting down finally. This puts wear and undue service time on the boiler and all its components. What might be causing this secondary and what should be unnecessary short demand for more heat? Thanks

Hi is the boiler on MAX ?

Mike

Is there a pressure vessel on your system
I have had a similar problem with my Boilermate A Class where the system water level must have dropped so it kept going on and off - I topped up just above the 1.5 bar and it cures it for a few months. The only other thing to try is swap your temperature sensors around if they are the same