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Added 9 zones - smaller nozzle?

Hikeman Member Posts: 1
Some time ago I converted my single zone oil fired hydronic system heating a 3600 sq ft to 9 zones - every room has a zone plus an indirect water heater. Kids are now gone and my wife and I live in one or two rooms most of the time. The boiler is a Burnham V86 with a 1.50 GPS nozzle @160psi. The boiler is, of course, way oversized now and occasionally short cycles. My question is should I go to a smaller nozzle (and loer psi) to have the boiler run more efficiently..All wisdom gratefully accepted!


  • astoria2013
    astoria2013 Member Posts: 16
    Had same problem.

    I have a smaller burnham in my house and had the same problem.  Looks like that boiler is rated for 1.9 gph, you are currently firing with that nozzle and pump pressure 1.89.   Now that boiler rating plate is for maximum firing rate, so yes I would try a smaller nozzle but leave pump pressure alone.  Try a 1.25 nozzle which would be firing 1.58 gallons per hour.  Mine made a huge difference when I cut it down a little. With oil consumption and cycling on/off. 
  • heatpro02920
    heatpro02920 Member Posts: 991
    edited February 2013
    A little more to it than that...

    Some people say not to underfire a boiler and run it in its spec range, but I have underfired many boilers over the year with good results... But...

    There is more to it than just changing the nozzle... Which burner do you have? You will obviously have to also change the air band settings, and may have to change the endcone and z dimension,

    Just last week I had a customer that is also a mechanical contractor, install a HUGE 6 section boiler in his 1400 sq ft home {he got the boiler for free when he did a gas conversion}. He threw in a smaller nozzle, and adjusted his fire, he couldn't get it rite, it would either soot up or make his smoke pipe glow... So he called me {I do a lit of his oil stuff, when he gets stuck}.

    It originally had an F31 head, 175psi pump psi, and 1.65 gph nozzle!!! I changed the smoke pipe from the huge 8" he had there to 6" with a nice draft reg {he had one of them tin pan types, I got him a field control} then I installed an F6 head, lowered the pump psi to 140psi {I dont like running suntecs over 140}, and installed a 1.10 nozzle with a longer angle and hollow pattern.... I figured I would go through 3-4 different nozzles trying to get it rite, but the first try and it ran great, pure luck.... a little draft reg, air band and z dimension fine tuning and that big boiler was running 84.2% with zero smoke, I was satisified....

    So like you see, there may be more to it than you think... But definitely worth doing, IMO...

    While you are there, install a Hydrostat 3250PLUS with an os100 odr, and a delta t circulator, do it all at once, like ripping off a band aid...

    PS: what is your heat loss? you are like 350K BTU lol....
  • pipeking
    pipeking Member Posts: 252
    soo true..

    you CAN NOT make any changes to your firing rate without a COMBUSTION ANALYZER.
  • billtwocase
    billtwocase Member Posts: 2,385

    this unit was set up, and hopefully tested with that nozzle. Any changes to fuel or air, it's gotta be tested, and burning right
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