Anything greater then a .65 70 wont fire?

BOB WILLARD

Just wanted to pass this to the board here--I been fixing burners for 25 years and cant figure out why when i go from a .65 70 (Delavan) to a .75 70 i get no fire??? Strange right?? Pump is good--Pressure 100-- Electrodes new clean and adjusted 100% and nozzle tube is new and clean...Transformer assy is new and clean-Spark is fine STRONG..I notice that the burner motor is a bit louder then normal and i'm wondering if i have a full 3450 coming from it? I do have 100 lbs of oil pressure so i would think the motor is ok.. Strange!!! I tried a few different nozzles at .75 70 and .75 80 no FIRE!! .65 70 fires right up!
There is also an OSV valve inline (disconnected that but made no difference...Thanks for any input.. Puzzled here for the first time in a long long time.... Thanks guys..
E G LIB

Dave Bush

Does any oil spray out of the larger nozzles, or are they dribbling?

Seems odd to me. What about a higher pump pressure?

[Deleted User]

Head/Static Disc/Low Fire Baffle

Some of the items that may effect you are the head, static disc and low fire baffle. I have never heard of this not letting a burner fire but if you do have insufficient air that may cause your problem. What boiler are you firing into? Beckett has a guide that will tell you which of each item should be on the burner.

tommyoil

If it fires at .65-70

Why are you trying to increase the firing rate? Whats the reasoning? I wouldn't find it strange if you are attempting to fire the unit for something its not rated for. I dont find it good practice to haphazardly stray from manufacturer specs. Is the head rated for what your attempting to fire? What is the condition of the head? What are your air shutter and air band settings? Hows the Z dimension? Did you yourself set up the Z dimension? Do you have the tool to set the Z ?? What do manufacturer specs call for? Wheres the low firing rate baffle? Do you need the baffle at higher firing rates? Whats the condition of the chamber? Is the unit plugged? Is the chimney plugged? Whats your draft readings overfire and at the breech? Pump pressure? Pump vacuum? What are those readings? Are those enough variables for you or shall I continue? The list goes on. The O.S.V should be of no consequense here unless its not allowing oil to pass in which case NOTHING would fire. Give some more info on the unit(make/model/head type on the burner)and try to get some answers to the above questions. Is it possible that someone besides you could have butchered up the unit somehow??? If it was your first time in the house you should be able to answer all of the above questions after doing a full unit evaluation. That would be my approach. The nozzle size is but one aspect of the overall picture. Dont try something that the manufacturer doesnt want or YOU will be held liable in the event something goes wrong. Give more info.

BOB WILLARD

BURNER TYPE ANSWER

Hello Sir-The burner is 1 year old The specs call for a .75.70 nozzle (SOMEONE USED A .65 70) I was simply changing to comply with the SPEC of the unit! The unit is a vert standing HOT air Rheem with a Beckett Burner..I have checked every option (Z dimension, Baffles.. The air supply is fine pump is great..Everything is clean and new--Fires great with a .65 unit CALLS for a .75--so i'm not trying to change something that shouldnt be changed as you can see--I'm simply installing a new Delavan .75 and the unit simply will not fire!! I have 3 .65 nozzlez--each one fires nice--I have 6 .75 nozzles Delavan/Hago/ New nozzles--Not one fires... PUMP pressure is 100 and constant and trans has great strong spark... When i put a .75 the nozzle pees oil but a .65 sprays nice!! STRANGE!!!!!!!

Firedragon_4

Doesn't make any sense and

my only question is if the 0.65 is working okay, why do this?

Ya can't fix it if it isn't broken, but you can sure screw it up!

joe_31

burner not firing

make sure you are using 70 solid nozzles also is it an f0 or f3 head is there a low fire baffle last be careful of a bad run of nozzles i keep a few danfoss nozzles on standby

joe_31

burner not firing

be sure you are using a 70 solid nozzle also is it an f0 or f3 head does it have a low fire baffle is blower wheel clean also get some other .75-80b nozzles could be bad run