Oil nozzle GPH

Patchogue Phil_32

I am curious about how a smaller nozzle and a larger nozzle affects both boiler operation and fuel efficiency.

For arguments sake, start with a boiler with 1.0 GPH oil usage and it is deemed to be the correct size for the BTU load in question.

If you go to an extreme smaller nozzle, is it correct that the boiler will run virtually non-stop trying to keep up with the load?

What if a smaller nozzle was used for 0.90 GPH ... would the overall oil usage be the same for the same BTU load? Or would you use slightly less or maybe slightly more oil to satisfy the same load?

Now what about using a much MUCH larger nozzle (forget about if it can burn thru the combustion walls), is there a point where the extra heat is just lost out the chimney because the heat cannot be transfered to the water quick enough?

What if a 1.10 GPH nozzle is used ... would the overall oil usage be the same for the same BTU load? Or would you use slightly less or maybe slightly more oil to satisfy the same load?

Weezbo

that is some what a good question...

down sizing a nozzel and making some adjustments can allow a boiler to run longer .... and use less oil.

over firing is tricky business as you have to take the heat for it,... depending on the flame type and the combustion chamber type though ,you can however, if you are having hellacious weather usually, first lower the pressure and increase the temp on your high limit as the first plan of action...it is safer and less of an argument.

and any sort of a by pass is a welcomed feature in that instance...a 10 foot washing machine hose usually will suffice....zoning is another place to look to hold against the cold.... dial down rooms you arent in....

the question you are asking is if the larger nozzle means it would bail more heat to the exterior...well you got to figure that the return water temps will go down when the boiler is not keeping up against the cold..then the heat transfer is better in the exchanger however if the flame is firing a long flame you should shorten it so that it heats more of the heat exchanger in places it never felt heat before:)remember you never heard any of this from me there is another thing sometimes the stack temp becomes a problem as the cold is like a heavy wet blanket over the fire box and you also have to frick with the draft....it is a liability in many ways so dont do it.

once a severe cold snap is over you have to go back and change everything .... the newer boilers might not be as forgiving so when in question call the manufacturer and ask for a tech rep.

ralman

I tried a smaller nozzle in my boiler.

My boiler can accept three nozzle sizes. I discussed with my heating company the possibilty that downfiring might save fuel for me and they said it might, so I had them install the smaller nozzle. It did not work for me. I feel it was due to the large water content of my system. Now I wonder if a larger nozzle would actually save fuel because the gross BTU output increases by 23,000. I think the larger nozzle would handle the large amounts of cool return water better.

Patchogue Phil_29

Weezbo...

...thanks for your thoughts.

Whn you said first lower the pressure and increase the temp on your high limit , you meant the water pressure right?

About that bypass suggestion.... and any sort of a by pass is a welcomed feature in that instance...a 10 foot washing machine hose usually will suffice ... does Taco make that adapter? [GRIN]


My questions weren't really aimed at a severe cold snap. More for the everyday running.

Thanks again,
Phil

Weezbo

yes changing the boiler temp up and the water temp down allows for the british guys to stay in the formula

i am not thinking that Taco has one of those automatic hose bib bypasses on the market just yet

i am really liking your splash of colour...any help on how i can do that? i always kick myself for not writing down the list of how to do all that when Dan posted it for us.

i like the green.

my e-mail is booga boo at the momment.
i will post a pic when i get back tonight ,for you ,it will seem unbeliveable truely astounding and utterly miraculous..:)

Patchogue Phil_29

Apples To Apples

Ross

I am curious how you made the fuel useage comparison? Was it gut feeling or did you calculate with temperature and extact fuel metering?

Patchogue Phil_29

splash of color



Not sure how Dan instructed but this is how I add color.

You use some HTML tags and something called inline CSS (Cascading Style Sheets).

Example, if you want the words "Primary-secondary is Da Bomb" to be blue and bold.... you precede those words with:


<span style="color: blue;font-weight: bold">
"then you put your phrase here".

Then you must finish with the end-tag for "span".

</span>



So you would type:



<span style="color: blue;font-weight: bold">
Primary-secondary is Da Bomb </span>

Which would then show as:

Primary-secondary is Da Bomb



There are the older simpler plain HTML tags for making bold or italic. Also for color. "Style" inside a span lets you do a lot in the middle of a sentence or paragraph.

ralman

comparison

My original nozzle was 1 gph firing rate. The smaller nozzle was .77 gph firing rate. With my original nozzle, a domestic hot water call or a heat call would last 4-6 minutes regardless of outside temperature. Burner cycles always lasted between 4-6 minutes regardless of any other factors. With the smaller nozzle, the domestic hot water call lasted 4-6 minutes just like the original nozzle. The heat calls lasted 10-12 minutes. Six 5 minute cycles per hour = .5 gph with original nozzle. Six 10 minute cycles = .77 gph with the smaller nozzle. The intervals between burner cycles stayed roughly the same as far as a thermostat call goes. It ends up, more 10 minute burner cycles during a 24 hour period with the smaller nozzle. When I say regardless of conditions, I mean I did this in January. So the outside temperature swings were not like say, October. Not exactly a scientific comparison, but I feel it was pretty accurate as I clocked the reason the burner turned on, the length of the cycle for 2 weeks a piece with both nozzles. I think if I would use the next larger nozzle, 1.18 GPH firing rate, the burner would run less, and inject higher temps into the loop, possibly increasing the duration between thermostat calls. Maybe some fuel savings there for my situation. I will check back later, I have to go to work now. Thanks, Phil.

soot_seeker_2

?


'course there would also be the matter of comparing the degree day loads for the periods running each nozzle. not sure if you accounted for that.

in a setup where the boiler doesn't make DHW (i.e. separately fired DHW) this comparision gets a bit easier.

2 cents..

Techman

Nozzles

Would down sizing the nozzle,from 1.0 to .90 and then increasing pump pressure so the smaller nozzle is equal to the original 1.0 nozzle in BTU input into the combustion chamber give a better overall efficentcy? That is assuming everything is sized and matched properly.Thanks!

Weezbo

*~/:)

*~/:)

Hmmmm.... it is something that eludes me:(

sea green is good

Patchogue Phil_29

don't forget

Weezbo

Once you "see" , it will be easy.

Dont forget the < and the "> symbols

Patchogue Phil_29

Don't forget

Weezbo

Once you "see" , it will be easy.

Dont forget to use the < and the > symbols.

An example, type exactly what is hilited in yellow:


<span style="color: green;font-weight: bold">
Hmmmm.... it is something that eludes me
</span>



This will show up as:


Hmmmm.... it is something that eludes me

Patchogue Phil_29

Any other thoughts?

Anyone else have any thoughts on my original question(s) about nozzle sizes?

Jim Davis_7

Firing rate

Underfiring will rarely if ever save money. It is usually just a bandaid for other mechanical issues. All equipment operates at maximum efficiency at maximum mechanical ability or firing rate. Not over-firing or underfiring. Heat exchangers have a specific mass that must be brought up to a certain temperature to heat the air, water or steam on the other side. A certain portion will be radiant heat from the flame which is the highest percentage of heat transfer and then convective transfer from the gases. Reducing either reduces their ability to transfer efficiently. Using smaller nozzles and raising pump pressure is a way to improve the operation of the burner and help increase efficiency.

Steamhead (in transit)

Do you have

a digital thermostat? If so, you should be able to adjust the cycles per hour. 6 CPH is a bit too frequent for a hot-water system, I'd change it to 3.

I'd also do a full heat-loss calc on the house, to see whether or not the boiler is oversized. An oversized boiler will almost always short-cycle.

To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"

Patchogue Phil_29

adjusting CPH

Please explain how that works? For your example of 3 CPH, does the digital stat limit a cycle to every 20 minutes if needed?

Or does it count 3 CPH even if they occur in first 25 minutes and then blocks any more for the remainder of the hour?

What if your 3 CPH has occured, and then you open the door a lot bringing in groceries and it is 6* outside and the room temp drops 15 degrees? You got to WAIT for the next hour of allowed cycles before the heat is allowed to come on?

Patchogue Phil_29

adjusting CPH

Steamhead,

Please explain how that works? For your example of 3 CPH, does the digital stat limit a cycle to every 20 minutes if needed?

Or does it count 3 CPH even if they occur in first 25 minutes and then blocks any more for the remainder of the hour?

What if your 3 CPH has occured, and then you open the door a lot bringing in groceries and it is 6* outside and the room temp drops 15 degrees? You got to WAIT for the next hour of allowed cycles before the heat is allowed to come on?