Oil burner too small?

Steamhead (in transit)

was the 73 series positive-pressure over the fire? If so the SF might not be the best choice......

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Roadfever2

Oil Burner too small?

Hello,
I am trying to correct some issues on our steam system to the best of my ability, one step at a time. One of the first projects I am planning is to add the correct number of vents to each of our 4 mains using the "Noel Method" from Gerry Gill and Steve Pajek's "Balancing Steam Systems". FYI - our current boiler is a Weil-McLain B-673-S steam boiler (Gross I-B-R output 434,000 btu/hr, I-B-R burner capacity 4.00 GPH, 12.96 hp). I do have all of the liturature for the boiler and the burner. One concern I have is that a few year ago, the service technician we were using at the time told us that by switch our old burner (Weil-McLain Model 45W-CU)to a Beckett burner (Model AFG 1192 .5-3.0 gph)we would use about 25% less fuel oil. I'm not seeing it. One difference I do notice is that the boiler runs a whole lot longer than it used to in order to get the building up to temp - sometimes more than an hour. Now I realize that a lot of this has to do with the fact that the steam mains need more vents on them and I'm sure there are other factors in play as well but I just get the feeling that the beckett burner may be under sized for the job. I am having the burner serviced in a few weeks by a reputable local company (the best company that I am aware of in Central Wisconsin). They are traveling about 45 miles so I'd like to give them the heads up if this might be an issue.
Question 1 - in regard to the burner size question, should my first step be to calculate the BTU capacity of connected system (radiators)? And should I include all insulated piping/mains in this calculation?
Question 2 - should I rectify the burner issue (if there is one) prior to testing to determine how many vents (Gorton #2's) I need to install?
I am obviously new to steam heating systems but I'm hooked. The more of Dan's books I read the deeper I get. I'm trying not to get in over my head but adding the correct number of main vents as the first step is an absolute no-brainer. I just want to make sure I have all of my ducks in a row before I dig in. If you guys need any more info for me, just ask. Thanks in advance for your help! Jon

Phil_17

Just another HO (pro's please educate me) and I've been addicted to this topic for going on three years now, but as I understand it:

1) Measure the EDR of all the radiators and use that to size the boiler (the boiler rating should have the pickup factor for the pipes built in).

2) The venting equation is based upon the volume of the pipes you need to vent and the time you are willing to allow for that to happen. Burner sizing should not be a factor (in theory). Just use the "Balancing Steam Systems" booklet for venting capacity and calculate the volume of your mains... Most people recommend that you shoot to have the mains vent in 2-3 minutes with less than one pound of pressure (4-6 oz seems to be the target)

Steamhead (in transit)

Depending on what firing rate

the Beckett actually uses, you could be WAY under-fired. 3 GPH is 75% of the boiler's rated maximum. The 45CU series burner was a not-quite-flame-retention sootmaker, so replacing it was justified. A flame-retention burner won't make soot if set up properly.

The burner I would have installed is the Beckett CF-375. Its maximum rate of 3.75 GPH is just under 10% lower than the boiler's rated maximum, but the difference is made up by the CF-375's hotter flame.

Also check the amount of installed radiation as PhilC says, and see how that compares to the boiler's capacity.

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Brad White_194

May need to be

it's own thread in a way, but as long as you are here, the burner size part is pertinent.

Your first point is correct, size the boiler by EDR.

The second point is correct on the venting allowing some minor opinion differences, but the burner firing rate (size for that matter) does have bearing.

A burner has to be matched to fire within the steaming range of the boiler it serves. There is some leeway of course, these are not precise, absolute devices.

But consider a tea kettle. A high flame makes steam in abundance. A small flame, too small a flame, may simmer, may even boil, make steam, but not enough to whistle, maybe barely enough to have vapor off the surface but not in the quantity to fill piping (if such were attached).

Trade in your Carlin, Becket or Riello for a candle and wait for steam, just to illustrate. You have to get that water going.

I have seen upward adjustments to oil burners make all the difference, between burning oil for 45 minutes and having cold radiators, to up-firing getting hot radiators in ten minutes. A lot of oil can be burned with no heat delivered and why do that...

[Deleted User]

In addition to

measuring the EDR, & firing as close as possible to that number, make sure the boiler is cleaned properly.

The 73 Weil has top clean outs, for the vertical flue passes, that can only be accessed by removing the top boiler jacket panels. If the vertical portion of the sections is clogged, some techs will down-fire to compensate for high stack temps & over fire pressure, vs. negative over fire draft.

Ray Mann

EDR of the radiators is

356,640 BTU/hr. The boiler manual rates the #73 @ a gross I-B-R output of 434,000 BTU/hr - is the 33% pick-up factor figured into this figure? I do have a Beckett SF series burner that has been used very little. Would this be an option or would a new CF-375 be a better choice? Can you guys give me a very rough idea of what it might run me for a new CF-375 installed?
Just a note on the EDR, the men's shower room is sort of a system within the system with quite a bit of exposed exposed piping (ranging from about 1 1/2" to 3" dia.) in the room (which also serves the radiators in the womens shower room directly above). I assume it was designed not to have insulation in this area as there are nice escutceons anywhere the pipes enter the room. I will try to get some pictures this afternoon. Should this exposed piping be added to the EDR of the radiators?
Thank You so much guys! I apologize, I should have asked these questions in seprate threads. My bad.

[Deleted User]

The 673

has a net rating of 325,600 btus per hour (1,355 sq ')steam. Your numbers indicate the boiler is undersized for the connected load. Properly insulated mains, & run outs, can mitigate the problem. Normally, the bare piping in the shower would not be a factor. However, it appears your situation is not normal.

The SF, w/ proper mixing components, should do the job.
Be sure to check those vertical flue passes.

RonWHC

Hi Frank.

Hope you had one for me @ BNL.

The 73 was the last 70 Series Dry Base Natural Draft Weil. Design fools some folks. Front top clean out door w/ horizontal flue ways. Or so it appears. The only way for the flue gasses to get from the chamber is up vertical passes, turn 180* over the top, & exit thru the horizontals.
Miss those top clean outs & you just may have a pressure fired piece.

The first pressure fired, wet base, Series 70 Weil, was the
pinned 76. BTW. The ABCs & Waynes that came on the 73 worked petty well - - until the boiler got clogged.

Steamhead (in transit)

In that case

the SF should work OK. Make sure whoever puts it in sets it up with a digital analyzer.

Thanks for the word, Ron. But the 45CU burners I've run into were rather problematic, especially on the 62 thru 66 boilers. Not sure if that burner was ever used on the 68. I generally replace them with current high-speed units.

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Ray Mann

Ron, are these the flue clean outs

you are referring to? About half of them just lifted off and gaskets fell apart. I have not attempted to remove the rest of them yet. I have pictures of the "seperate system" in the men's room as well but I will probably put them on a new thread. I had to show off the men's room a little though. We been working really hard on that project and I though you guys would appreciate seeing it.

[Deleted User]

Yep.

You can make new gaskets from Kaowool Blanket.

Near boiler piping is problematic. Like the men's room. No excuse for missing the target.

Jim Davis

Excellent Brad. Burners heat boilers not houses. The burner must fire at the rating of the equipment not the home.