Because he doesn't know that he just down rated your boiler and made it run worse?
Most today use a smaller nozzle with higher pump pressures to get better atomization. You get the same results because higher pressures move more product through the nozzle so you make the nozzle smaller. They have charts.
If he can't explain why he did what he did, you might consider someone else.
Or maybe he didn't have a smaller nozzle and he lowered the pump pressure thinking it compensates.
Or he doesn't understand proper combustion and all its elements, especially draft. When he looks at the fire and lowers the pump pressure, it looks 'better' to him. Maybe poor draft or partially plugged heat exchanger (poor, lazy cleaning), has the flame impinging off the back and this is his remedy.
Either way, get a better guy if you can.
This post was edited by an admin on February 22, 2014 6:19 PM.