I have a customer with a warmflow white utility 70 oil boiler. boiler refuses to light. I have changed the nozzle and fuel pump and set the pump pressure to 8 bar as per manufacturers instructions. The boiler motor runs, solenoid opens, sparks but no ignition ?? Oil appears not to be vaporizing at nozzle, just squirts out Think the customer might have put red diesel in the fuel tank. Would this cause this ? any help would be greatly appreciated.