burner replacement on oil boiler

I have a grant 50-90 oil boiler. The burner needed replacement. The heating engineer installed a Riello 40 burner even though on the quotation he said he would install a Riello 50 burner. The house is a standard 3 bedroom semi-detached house in Dublin, it has 8 radiators - 5 single radiators and 3 double radiators. I was wondering is the Riello 40 burner sufficient for the amount of radiators in the house?

The Reillo 40 burner would be the standard burner fitted to the vast majority of those boilers and should be perfectly suitable.