Switching from 35 Sec oil to 25 Sec oil - Nozzle size

[Domcr250]

Hello all,
Simple question – I’ve competed my OFTEC training, mainly because our house has a very old Ideal Standard boiler house boiler running a Nuway NOL2 burner.
The course has paid massive dividends, by putting in the correct nozzle and resetting the pump pressure I’m now running at 11.5%% Co2 and using about 7 litres of oil less a day!
Problem is I’m running Red Diesel (35 Sec), it’s about 10 pence per litre more expensive than 25 Sec Kerosene – so I want to run the tank empty and switch over. But what Nozzle do I use?
Currently it runs a 0.85 60 degree solid at 175 PSI, I think I would need something like a 1.10 60 degree ES Nozzle and reset the pump to 115 PSI to maintain the same heat output?
Any thoughts?
Many thanks,
Dom

 

[pmac10]

did the OFTEC training about a year ago but i dont think i would change the nozzle, if i remember right these are specified in the Burner manual along with pump pressure. the 0.85 degrees i think is the angle of spray, 60 is US gal/hour and changing from S to ES, well when i went to change the nozzle on my own burner last year (0.80 60 S), the plumbers merchant reckoned the ES was just the new more environmentally friendly version of the S?
just stick to the manual.