How long should the burner fire on a design day?

Weezbo

last week it was 45 below at my house :)) hey and winter isnt even HERE YET :))i dunno buh at -62 degrees i got to think a wtgo4 ould be purring along not even thinking of taking a break :)) you guys must have southern boilers or something :) call me back in or near the 22nd of January and i will try to give you a clearer answer.at 2 degrees at this time of year i would expect that designe temp isnt even being approached....maybe winters different where you live...is it almost over or something? geez that Would be good news :) Hurray ! now i can call the guys up and tell them turn the heat off and get back to work! we are experiencing a HEAT WAVE! :))) sorry...if your designe temp is 2 degrees ,which it could be ...the boiler would be purring right along with some shade of leeway ...

Steve Garson_2

How long should the burner fire on a design day?

This morning was our first "design day" with a temp of 2* above zero. My house recovered from a 7* set-back with 80 minutes of burner time. After reaching 69*, the temperature was steady for the next two hours with fifteen minutes of run time. This evening, it's 10* outside now and the burner is running only five to six minutes an hour.

This new boiler is a WM SGO-4 with a 1.1-gpm nozzle. My house is well insulated.

Is my boiler over-fired? My only reason for asking is that some of my vents whistle on the steam cycle, despite Gorton vents on radiators and mains.

Any steam pros that can advise me? If my description indicates over-firing, what nozzle would I tell my oil company to install?

Ken D.

Burner.

Ideally, it should be six cycles per hour. The outdoor temperature is a big varible.

jeff_51

can't answer about nozzle size

but I like to undersize boilers. Like to see them run about 50 out of every 60 min on a design day (not really undersized even at that) 'cause we can go way below design temps for days. Sound to me like you are overfired for your needs

brucewo1b

Weezbo,

""2 degrees at this time of year i would expect that designe temp isnt even being approached....maybe winters different where you live...""

I think you might have gotten a bad boiler because when its 64 degrees above design temp here I don't expect mine to run except for an occational HW demand.

Steve Garson_2

While I can appreciate the sarcasm, in Boston, the design temp is 0*F. We're lucky to get one day below 0*F every two or three years. This is very ususual to have these temps at this point in the winter. This AM it is -1*F. Burner is running twelve minutes an hour with 69*F indoor temp, with two six minute cycles, since the Vaportrol is cutting out at 8 ounces.

Fred Harwood

Nozzle

You could try a 0.85 gph nozzle, if it lights well, and the efficiency stays up (use a combustion analyser).

Also, how full does each radiator get on steady-state cycling? As the outside temp goes down, more of the rad should fill. The rad should not fill each cycle, unless you're at design and your rads match your heat loss.

[Deleted User]

Theoretically speaking...

All things being equal and propelry sized, the heat source should run full out at design condition. With that said, on systems that I know for a fact were properly sized using standard industry practices, I've never seen a space heating boiler running at more than a 50% duty cycle, even at design condition.

It does sound as if your heat source is oversized, and not being an expert in oil, I can not make comment about under firing or under sizing. If were talking water instead of steam, throw a modcon boiler at it and watch your fuel bills drop.

The mod con boilers size themselves to the load. When I first fireed mine up, it ran FOREVER. Never hsut off. Ikept thinking to myself, "When the wife gets this months gas bill she's going to KILL me..." When the bill finally came, it was 30% less than the previous years bill and it had been colder this recent period.

MOdCOn is the ONLY way to fly, high temp or not.

ME

Dale

Never shut off

At design the thing should never shut off and still keep your house at whatever design temp was used, like 68 or 70. Having said that I know of only one house where that happens and then with a strong north wind. Heating only the software will show about 40K for a 1400sqft. moderately insulated house. So, see what is the smallest size nozzle your boiler is rated for and have a tech set it up that way, you already know the one that's in there is bigger than needed, also you can think about constant circulation if the piping warrants it as well as outdoor reset.

Steve Garson_2

My radiators get hot accross all the sections at this temperature, with just 12 minutes an hour of cycle time.

Steve Garson_2

So the big question is: with a 1.10 gph nozzle now in place, do I try a 0.85 or a 1.0? If my system works with the smaller nozzle, do I essentially use the same amount of fuel oil, but it just takes a bit longer to generate steam?
Will I use more oil?
Will my oil dealer know what angle to use with my WM SGO-4?

Thanks!

Constantin

I'd contact the manufacturer...

... and see if they can provide any guidance. Chances are, the manufacturer will not be happy about any significant reductions in nozzle size. I wouldn't attempt anything outside the recommended range, simply because it opens you up to all sorts of cans full 'o worms. Presumably, so would most professionals (I'm just a homeowner).

I know one luminary over at OTT who is firing his boiler at something like 1/4 the recommended name-plate rate, but he's a luminary, and it's a direct vent system heating a hot-water boiler. In other words, unless you're an oil boiler expert (and it sounds as though you're not) and own the kind of system that can handle this drastic of a reduction, I would not try this at home.

Mike T., Swampeast MO

You're not speaking theory--you're speaking FACT!!!

And yet people STILL OVERSIZE--even with modulating/condensing boilers!!!

it ran FOREVER. Never hsut off. Ikept thinking to myself, "When the wife gets this months gas bill she's going to KILL me.

EXACT same situation. How can you save money if the boiler doesn't stop running???

Politely pester manufacturers to introduce SMALLER modulating/condensing boilers to the American market!!

thp_8

All Things Considered

Mod Con better on fuel = waste on operating system, boiler pumping & increased electrical consumption. Would you idle your car 24/7 ? Think about it.

Steve Garson_2

Getting back on topic...

What do I tell my oil service company to do? What size nozzle? The old 70 year old steamer had a 0.85 gph nozzle.

Steam pros?

Steve

Weezbo

when it goes Cold and deeper cold....

i swifty change out the nozzel and reset the burn. i recommend that people have a tech come by their house first thing they can in 30 below and re tweak thier boiler for winter.

it is currently 16 above again We Really Do have a HEAT WAVE *~/:) if as you say the boiler is sized properly for the deppest cold your boiler itself should be purring right along with some room for the DHW ...

rich pickering

At -40, my service van runs until I get home.Far north construction sites, vehicles run 24/7.

Weezbo

Steve, my riello F-3 just fired for 4 mins.

it is like 16 above and snowing to beat the band.it has a .5 one of thesmallest nozzle sizes available. it is bolted up to an ancient 666 or basically a front and back and thats it for the most part the weil mclains of the 4 section variety i install with a F-5 riello what it sounds like to me is you could have used a 3 section so can you use a smaller nozzle. sure the only thing is you want to make sure to keep the stack from being out of the green as i call it. my burner just fired again...so i am having like 4 min run times and 16 min roll time..i have constant circ...it only shuts off when i disconnect it in summer.the radiant portion however i leave running 24 7 365.25 a boiler tech can take all the readings on the stack pressure at the nozzle co2 O smoke and draft,put a range of nozzles in the boiler the specific size though and angle is up to him...there are suggested sizes pressures blah blah bla however it has to check out so inother words tell the guy you think the run times are too short and you would like to get longer run times out of it...by boiler has L vent. it doesnt go into a masonry chimney out the window thru the floor meander around in the closet back and forth thru the basement it come straight out the back and straight up passes thru a 3.5 12 pitch goes two feet abve the crown bang done deal. 5 ' of l vent 2'-6 "of 24 gage.every stack and its length and size have a bearing on what's what. there are a lot of variables that infuence the burn.there are variables within different burners and even within the same burner... people who make a living servicing oil burners know how to change the gun air shutter pump pressure draft stack temp to achieve the most out of a burner and the heatexchanger it is lashed up to. much as someone who is a professional photographer choses the f stop and shutter speed the grain lens stop bath fixers to dial the most out of a panoramic ...telling him to use an fstop and asa is likely to urinate him off more than help get the best out of your camera.. just tell the guy what the picture is you are wanting to see and There it is.

Weezbo

There is truth in that too Rich.,

plenty years of that..

[Deleted User]

Why is it...

that I get chastised for using an automobile analogy but it's OK for you to use one???

Painfully yours...and still wondering what the heck your real name is. I know someone here knows it, and I could ask him, but that would be WAY too easy ;-)

Why hide?

ME

Marty

I'm not an expert

Odds are the boiler is sized to the radiation, Kinda have to do that with steam. Be willing to bet the radiators have way more capacity than needed especially if insulation etc. has been done over the years.

Constantin

That C-5 still bothering ya?

Presumably, you wouldn't have taken the bait otherwise... As for the car analogy and mod/con, I have no idea how "thp" dropped in on that tangent in response to my post. I thought we were discussing a steamer here, and a noncondensing one at that. All other things equal, I'd like to think that an oversized boiler will have higher standby losses via the jacket and the flue than a properly-sized one.

thp_8

Constantin

The car thing was not for you. I was just following the time line. I think it's fitting for that application. Looking at it from a standpoint that power consumption of the mod-com varies only slightly from lets say 20,000 to 200,000 btu's. Just an idea to think about.

Fred Harwood

nozzle

> My radiators get hot accross all the sections at

> this temperature, with just 12 minutes an hour of

> cycle time.

Fred Harwood

Nozzle

Sounds as if you're overfired a bit. When the rads get hot all the way across each time before the heating call cancels, the rooms probably overshoot. For example, in a 1950s well vented single-pipe I tend, at 20F outside the boiler runs perhaps 5 minutes and a few seconds three times an hour without heating the rads all the way across and without building pressure. The room temps are stable and even between rooms. A recording temperature gauge near the thermostat shows no discernable blips or dips on cycles. As the temp drops, more of the radiator heats.

Constantin

... and?

If the mod-con boiler consumes very little energy to start with, it's a non-issue, right? Hydronicsmike and I went through this excercise last year, where we calculated that a standard 85W pump consumes something in the range of $25-35 per annum. That's less than 10% of the heating bill for most people.

According to ACEEE, the modulating, condensing boilers are also not created equal in terms of electrical consumption, the Vitodens for example was listed as consuming 8x less electrical juice than a comparable WM Ultra, IIRC. However, I do not know their testing methodology and I imagine that the electrical consumption of the circs used to "feed" a typical system dwarfs the power used by just about any non-electric-fueled boiler.

Constantin

... and?

If the mod-con boiler consumes very little electrical energy to start with, it's a non-issue, right? Hydronicsmike and I went through this excercise last year, where we calculated that a standard 85W pump consumes something in the range of $15-35 per annum. That's less than 10% of the heating bill for most people.

According to ACEEE, the modulating, condensing boilers are also not created equal in terms of electrical consumption, the Vitodens for example was listed as consuming 8x less electrical juice than a comparable Burnham Revolution, IIRC. However, I do not know their testing methodology and I imagine that the electrical consumption of the circs used to "feed" a typical system dwarfs the power used by just about any non-electric-fueled boiler.

Below is a calculation for a 85W pump feeding a system 180 days a year (which I think is pretty generous). Compared to the cost of the fuel being fired, the electrical costs are pretty insignificant to anyone who benefits from being tied to the electrical grid.

thp_8

If

you bothered to look at alot of these mod jobs, they are not running little 85watt circs. Also not just 1 but dozens. So please multiply your figures by about 10. Alot of times it's the things you don't see.

Steve Garson_2

Contacted Weil Mclean today. They advised me that you can reduce the firing rate no more than 20%. Any more than that will result in rapid soot build up in the combustion chamber.

Since I have a 1.1 gph nozzle in there now, it sounds like 0.9 is the smallest I can go.

Next question: should I have the contractor who did the install perform this work, or my heating company? Should I be paying for this labor with my contractor, or not? I just want to do the right thing.

Any steam experts wish to chime in?

thfurnitureguy_4

Steve, Don't go nuts with the smallest nozzle. It is easy to over shoot and get a slow to no steam up and killer long run times. This is not good either.

Constantin

...well then allow me to quibble

I thought the issue here was the electrical consumption of the boiler running 24/7 modulating up and down, not the electrical energy consumption of the distribution system (i.e. the balance of plant) its attached to. Naturally, any hydronic heating system that has a forest of circs whirring away will have a higher electrical power consumption than one where the circs are sized to the load.

However, that has nothing to do with a modulating condensing boiler but the BOP. All things being equal, the BOP attached to a atmospheric boiler will still consume the same amount of electrical power as when it's attached to a mod/con boiler. I suppose a steamer could obviate the need for circulators but hydronic gravity systems from yesteryear also managed just fine without circulators.

Several contractors here have had great success heating large mansions with 3 circulators or less when tying a mod/con boiler into an extant gravity system while avoiding to over-pump it. For example, Mike T. from Swampeast only uses the variable-speed circulator installed in his Vitodens for the whole system.

thp_8

I Guess

I have always taught myself to look at the whole system. Not just one part of the system. Then evaluate the system down to the least power consumption. To me that only seems logical.

Constantin

... and how is that different from what I espouse?

First you criticize the energy consumption of a mod/con boiler on the basis of it running 24/7. Then you shift your ire to the BOP, which may, or may not consume a lot of electrical energy. Now you call for a holistic review of the system. Perhaps I'm being dense, but from my side of the internet, your posts represent a moving target, at best.

Well, have a look at the ACEEE list of boilers that I salvaged from the wayback machine. As you'll see, there are boilers which consume more or less power than a mod/con boiler. Yet, in none of the cases do the boilers consume vast amounts of electrical energy. Said boilers max out at about 355kW per annum, which is still less than $50 in most states.

According to the data presented by the ACEEE, If overall power/fuel minimization is the target, a modulating condensing boiler like the HTP Munchkin, Viessmann Vitodens, or WM Ultra combined with a gravity hydronic system is the way to go as said data shows these mod/con boilers to consume less electrical power than most of its non-mod/con competition, while always offering higher fuel efficiency when used in conjunction with a proper distribution/emitter system.

And, ever since that list was released, a whole slew of worthy new mod/con boilers like the Knight, Prestige, etc. have hit the marketplace. Naturally, it is entirely possible that the methodology used by ACEEE is wrong, non-applicable, etc. in which case I invite you to hunt down and present some data .

thp_8

Not me

Criticize mod-cons, I work with them everyday. As far as manufactures specs. Very few are rated the same. So thats a non issue. All your literature and stuff, thats called marketing. Industry puts more money in marketing than the actual products, because thats what sells it. The point is that the theory and properties of combustion have not changed since the cavemans first fire. For the Munchkin thing, since thats a forced boiler, your system would not be gravity anymore. P.S. Merry Christmas.

thp_8

Not me

Criticize mod-cons, I work with them everyday. As far as manufactures specs. Very few are rated the same. So thats a non issue. All your literature and stuff, thats called marketing. Industry puts more money in marketing than the actual products, because thats what sells it. The point is that the theory and properties of combustion have not changed since the cavemans first fire. For the Munchkin thing, since thats a forced boiler, your system would not be gravity anymore. P.S. Merry Christmas.

Constantin

Interesting...

... can you back up your statement that "Industry puts more money in marketing than the actual products, because thats what sells it" with a certified annual report and/or 10K that shows that the advertising expenses for a boiler manufacturer exceed the cost of goods sold, as you imply?

This is an age-old allegation that is preferentially leveled at EU-producers of boilers, yet no-one has produced proof...

So, I would appreciate if you could point me towards a certified annual report of a boiler company or a credible product-specific cost report where the SG&A exceeds the COGs? (and advertising is usually but a small fraction of the SG&A). Frankly, until someone antes up a certified proof, I'll relegate this allegation to the rumor mill.

Merry Christmas to you too.

thp_8

Do me a favor

just call your local supplier, (that's right you don't work in the field) or call a manufacturer and ask the number of salespersons vs. R&D or tech. reps. See what answer you get.

thp_8

Do me a favor

just call your local supplier, (that's right you don't work in the field) or call a manufacturer and ask the number of salespersons vs. R&D or tech. reps. See what answer you get. As far as putting more money in advertizing than the cost of the whole product that would be kinda be stupid. I am not a good saleman, but I would not even do that. But you can twist the words anyway you like. P.S. Merry Merry Christmas.