Thanks very much John. These screen shots tell me virtually all I wanted to know. When you attached the burner sequence image yesterday I studied it and noticed that when boiler burner runs two motors are energised and only one when cooker burner is live. I assumed at the time the cooker motor is supplying cooker fan and pump and the boiler motor just a fan. Reading what you just attached confirms my thinking. One last thing I’m curious of and that you might be able to find is how the soft start pressure is governed. These pumps have a single regulating spool inside them, with the theory of say 10 bar setting at pump = 10 bar at nozzle but as you know the soft start on this unit is 6 bar so unless I’m being stupid there must be something else initially adjusting this pressure.
Thanks for taking the time so I can get a better understanding of these units, much appreciated and I’m glad you managed to find a decent engineer who fixed your problem.