Can I make my boiler smaller by reducing nozzle size?

Hey_Obie

I currently have an old oil boiler that is large for my heating needs.  It has a 1.35 gph nozzle and 145,000btu.  Can I simply put a smaller nozzle (say 1.0) on the burner to make the boiler appear smaller so that it is more efficient?

What problems would the smaller nozzle create?

Thanks,

Obie

Charlie from wmass

Simple answer is No.

the burner needs to be tuned to the new nozzle, also some internal parts like the flame retention head may need changed to match the new fire rate. Find a pro and have them see if it can be derated. problems like low stack temps can cause issues if it is fired too low.

Ron Jr._3

What brand boiler ?

The newer oil fired boilers we install nowadays give you a fairly wide range of inputs ( in the same boiler ) . Some can be increased or decreased by as much as .50 gph . I don't see a problem downfiring as long as the flame is clean and you keep the net stack temp up enough so the boiler or venting system won't rot out from condensation . If it's a real old boiler ( big passageways ) I can't see that happening even with the lowest size nozzle you can use with your oil burner .

Big Ed_4

Dropping input

1.00 GPH with 100# pump pressure burning #2 fuel oil = 140,000 btus input ... 1.35 GPH would be around 189.000 btus input @ 100# pump...



Drop down input too far and so would your CO2 reading and as stated stack temp dropping too low ... a safe rule of thumb..... Stay 80% of the boilers max input on a negative pressure boiler .. A positive pressure boiler you want to stay very close to it's designed input ...



As mentioned the burner may need a different end cone if input falls out of its range or sometimes a new burner ...

Hey_Obie

Thanks