With this type of boiler, what typically would the burner consume for gallons of oil per hour. Are the nozzles rated that way or are they by opening size?

 

The nozzles are rated, and different size nozzles could be used in a particular burner. Even the nozzle rating itself may vary if the fuel pump pressure if higher or lower than that used to rate the nozzle.

 

Fuel oil nozzles are rated by Gallons Per Hour . A 1.25 nozzle would be 1.25 Gallons per hour AT 100 PSI PUMP PRESSURE.

100 PSI is the minimum pressure used, and what the nozzles are rated at. Recently most manufacturers are using higher pump pressures, and smaller GPM nozzles. This provides better atomization of the fuel and better burn patterns.

There is also a spray pattern designator for the different nozzles. These pertain to the way the fuel is sprayed. A 90° nozzle for example would have a wider pattern than a 60° nozzle.

Additionally, there are three basic 'types' of pattern; SOLID, HOLLOW, and SEMI-SOLID .

If you look at a Delavan nozzle as an example, you might see:

1.25 80 B

This would be a 1.25 GPH 80° angle SOLID (B) pattern.

What's in your boiler is anyones guess ! Being a retro-fit, the technician that did the work would have hand selected the best nozzle based on his test equipment measurements of SMOKE, CO2, O2, CO ... and his experienced eye ...

 

So if I understand this correctly assuming a 1.25 gph @ 100psi, that for each hour I would use about 1.25 gallons of oil. If for example you used a 1.0 gph at 125 psi would you use 1.0 gallons per hour or would you use more because of the increased pressure?
Is this 1.25gph nozzle a common size and how much bigger do they come?

 

First part, yes, correct. At 100 PSI, a 1.25 GPH nozzle would spray 1.25 Gallons in an hour of burn time. plus/minus manufacturing tolerances (maybe 5%).

Second part, no, a 1.00 nozzle at 125 PSI would flow more than 1.00 GPH. There are charts that would tell you exactly how much. If interested, I'll see if I can find a link to one.

OH, they go a LOT bigger than 1.25 ! maybe 10 GPH, maybe more, but you will NEVER see these in a residential boiler.

The size of the nozzle depends on the BTU of the boiler.

Fuel oil is around 140,000 BTU per gallon. So, if a boiler were rated at a GROSS input of 140,000 BTU, it would have a 1.00 GPH nozzle. A 1.25 might be used in a 175,000 BTU gross input boiler.

I would think that MOST residential boilers in the majority of homes would use a nozzle between say .65 and 1.50 , unless it was a McMansion, then maybe a little bigger ...

 

Trooper made a very important statement which included "burn time". People not in our industry thinks a 1.25 gph means just that. Every hour it burns a 1.25 gallons. The nozzle only burns the given flow rate when the burner is runnig. If the burner runs three twenty minute run cycles in 3 hours it used 1.25 gallons in three hours on the clock but only 1.25 gallons in the hour of run time.

 

So if I put some kind of (electric) time meter on my oil burner voltage supply, I could then calculate how much oil was used (assuming 100 psi, and known nozzle GPH)? I use a 1 GPH nozzle in my burner and it sure doesn't seem to run anywhere near 3 hours a day but that is roughly the rate we burn it in winter (200 gallons goes a bit more than 2 months in southern CT). It would be interesting to check. Anyone do this (and what/where did you get the timer)?

 

Trooper has... he used an electric clock. A dedicated hourmeter is best and they can be had very inexpensively.

Get your tank filled, start using it and then when you get you tank filled next time you should be able to extrapolate the GPH for your heat. When I had my oil boiler, that wonderful sound of the Reillo boiler meant both comfort and $2/hour.

You'll have a slight bit of error for having the clock running during pre and post burn phases, but if you aren't cycling excessively it shouldn't be too much.

The other thing you could do, is wire your boiler leads into a temporary plug and then plug that into something like a WattsUp Pro that can actually graph your electric consumption. This of course involves risk with electricity and snoopy inspectors showing up at the wrong time. But it will give you what you're looking for -- heck with the new net version you could monitor the boiler online.

 

>If for example you used a 1.0 gph at 125 psi would you use 1.0 gallons per hour or would you use more because of the increased pressure?

The math to calculate the nozzle flow when the pressure is changed is straight forward. It is the square-root of the pressure difference ratio times the nozzle rating.

NewFlow = RatedFlow * SqRt( NewPSI / 100 )

For the above with a 1.00 GPH nozzle at 125 psi. Will use 100 psi as the base as that is what residential nozzles are rated at:

1.12 gph = 1.00 * SqRt (125 / 100)

The 1.00 gph nozzle will flow 1.12 gph at 125 psi pump pressure.

The Windows calculator will do square root by checking the Inv box and then the SQ button (x^2). Be sure to put the calc into scientific mode for the full button array.

Al.

 

Yes, I've got an old electric wall clock wired to the OIL VALVE on my burner, so it only runs when the valve is open, eliminating the error that Who mentions. With the clock (or hour meter) wired this way, it will not run during pre and post purge times.

At my last fill, I had calculated that I used 189 gallons. My fill was 192 gallons... not much error there !

 

Thanks guys. Maybe McMaster-Carr has hour meters.. I'll look.
The WattsUp sounds like an interesting device too. Expensive?

 

The prices are at www.doubleed.com and the darned NET version aint shipping 'til April now. They had said Feb and mine's an old one with a serial interface that I'd like to update.

Figure $150 to have graphing, but these are great for doing any electrical consumption analysis under 1800 watts...

 

i am also trying to configure a way to calculate/monitor oil consumption.

has anyone had any success using an hourmeter? if so, which 1 did you use? i've ordered 2 of the ENM 115vac digital variety and neither of them would work. I would splice it into the wire going to the solenoid on my oil valve, but neither would pass electricity through. i didn't get any reading on the display and obviously the boiler would not fire. what am i doing wrong?

 

You evidently connected the elapsed-time meter in series with the valve. It has to be in parallel. Wow. What kind of engineer is your occupation?