No way I would ever give up the steam. There`s nothing like it. Best heat period.
The only less efficient and costly way to heat would be a fireplace. Before you can even think about getting heat, the boiler has to raise the water temperature to 212 degrees. 1000 gallons a year is what 38 hundred a year at current oil prices. It's insane to keep that old pig. Take out a loan and rip all of that crap out of your house and replace it with forced hot water. If you go with high efficiency stuff you can even get a tax credit
[B]No, plumbing ain't rocket science. Unlike rocket science, plumbing requires a license[B]
No way I would ever give up the steam. There`s nothing like it. Best heat period.
With steam systems matching the burner size to the radiator surface area is the most-critical aspect in a replacement scenario.
Oil exhaust condensate is pretty acidic, but most steam boilers operate at a sufficiently high temp that flue condensation is usually minimal. (But after 70 years of oil burning just about any ceramic/masonry flue would be due...)
At 1000 gallons/year of primarily space-heating you'd probably be cutting 300-400 gallons off the annual fuel use with a new steam boiler (they still have plenty of mass- better insulation too.) But if your floor plan was amenable to heating with a mini/multi-split heat pump you might get a better return on investment out of the latter.
Don't be counting on the cost of heating oil to come down for the intermediate term- if anything it's poised to RISE again as the world economy picks up. Heating oil shares the same fraction of a barrel of oil with diesel, which is the fuel-of-choice in Europe these days, and in much of the developing world. During the peak of '08 people were saying we'd never see $3 heating oil again- I was of the opposing view then (and I turned out to be right) but I also believed at that time (and still do) that there is $5 heating oil in our none-too-distant future too. By contrast natural gas pricing it likely to remain relatively stable, or at least take a lower inflation track with lower volatility than oil, due to the large domestic reserves of shale-gas discovered in NY/PA. If you're anywhere near a gas main, biting the bullet on gas service might be "worth it" if/when replacing the steam boiler with a newer one, but it's usually a hunk o' change, something that needs a careful financial analysis. But long term, looking at another strategy for heating the place is in the cards. At $3500 year it's already pretty steep, but a sustained price shock like that in 2008 can make all sorts of things "pay back" in very short years.
Ductless mini-split heat pumps can handle most of the load for most of the year, and even at Long Island's ~20cents/kwh rate would be far cheaper to heat with than even $3 oil in your ~50% steam plant, if you follow the arithmetic in the example I did for Olimazzi back on the 25th. Oil in your boiler is almost as expensive as electric baseboards at your current oil & electricity rates, but with a ductless mini-split the same amount of heating costs half as much or even less. (It's about 0.4x as much, or a ~60% discount.) If oil goes up faster than electricity, ductless heat pumps are an even better deal. I don't expect to see oil prices dropping by half.
So if I turn the low limit all the way down the boiler shouldn't cycle much to maintain temp, correct? (coil has been cut off).
Right now I have the Low limit to 0 and the high to 120 for the summer. I hear it kick on a couple times a day. (don't want it to go cold for fear of a leak).
And for the winter should I keep the low to 0 and put the high around 180?
I'm thinking since there is no coil in the picture anymore (electric water heater), the low limit has no purpose.
Thanks for all the help guys.
Zero, as in 0-degrees F? there'd be no reason for the burner to ever come on, and if it did because it got to zero, it would be shot since it would be a solid block of ice. On these old boilers, you need to watch the flue temperatures, and I do not think those settings would keep your heat exchanger from rotting out in a short time, or your flue. Plus, the temp variation would likely cause leaks.
Important note - I'm not a pro
Retired Defense Industry Engineer; Schluter 2.5-day Workshop Completed 2013, 2014
Not sure how it's ever getting down to 0F in summer, but when it does you sure don't want the burner to fire, since the freezing of the water will surely have split the boiler wide open in several spots, eh? ;-)
I doubt we really know what temperatures the controls are keeping it, but is sure isn't 0F. But if you are hoping (for no really good reason) to keep the beast around through another heating season, setting the hi-limit to 150F is probably prudent.
In the two heating seasons since this thread began, a ductless mini-split heat pump would probably have already paid for itself in oil savings. Waiting for heating oil to drop back to a buck-fifty a gallon or something? Get off the oil- don't wait- a combination of a mini-split and a few electric cove heaters (preferably on occupancy sensors) on the doored off rooms can take a huge chunk out of the heating cost, reduce your global warming footprint, and help both the regional and national balance of trade issues, according to this recently published policy piece (most of which is close enough to the real numbers to matter.)
Hey guys, wen I turn the dial on the low limit all the way down it's at 100, not 0 - my mistake.
So low is all the way down at 100 and high is at 120. I don't hear it firing - it's been 80-90F here recently - so I will turn the high up to 150.
Took a look at the cove heaters - pretty neat idea. Can ya give me a link to a good mini-split system?
Mitsubishi, Fujitsu, and Daikin together own something like 3/4 of the market in the US, with Mitsubishi the clear sales leader (if not necessarily the efficiency or innovation leader.) If you stick with any of those three you will probably have multiple levels of technical support & expertise. What you're looking for is a good HVAC contractor to advise on ductless mini-splits- there are many good mini-splits, not quite as many good HVAC contractors.
The competence and thoroughness of the installers will vary by quite a bit. I've grown to be highly skeptical of heat load estimates of those in the HVAC trades, and would either do my own or hire an energy nerd who has the right tools & knowledge before embarking on any new system. Oil use numbers can usually put a number on the whole-house load, but room-by-room load numbers are necessary in order to optimize the mini-split head (or heads) location(s) and size(s). All good heating systems start with a careful load analysis.
To sketch out a heat load for each room, you'd need to know how many square feet of exterior wall area, window area, the wall construction type & insulation values, the window type/U-factors, upper story ceiling & attic R, etc. We'd also need to know the exact location (zip code is good enough) to divine an outside design temp. This can all be done on a spreadsheet tool in a fairly straightforward manner. With the construction type & R values we could estimate the U-factors of the walls and ceiling, foundation etc, and throw in some air-leakage fudge factors- it doesn't have to be super-precise for sizing mini-splits but you don't want to end up oversizing by more than 50%, nor do you want be undersizing it for the spaces directly served.
Looking back to my quick & dirty analysis of your fuel use from a coupla years ago it looks like you have a 1400' house in a location with about a 10F outside design temp, and a heat load at 10F of something like 20-25,000BTU/hr (credible, but not etched in stone- do the room-by-room calc), which is approximately the output of a 1.5 tons of mini-split at +10F. If the floor plan is fairly open you may opt for a single head, and use cove heaters for balancing any critical doored-off rooms that wouldn't convect freely to the main space, but if it's a couple of large spaces it might be better to use two, maybe a pair of 3/4 ton units or heads (depending on whether the refrigerant lines to a 2-head multi route cleanly, or whether it's easier/better to use separate compressors), or a 1-ton + 3/4 ton, etc. This is not something well suited to design-by-web-forum, but if you take the time to do your own room-by-room heat load, and sketch up a floor plan, maybe. It's a worthwhile exercise even if you ultimately hire somebody, since you'll then have a better handle on what it really takes, and whether they're actually giving reasonable service. A single 1.5 ton name-brand mini-split runs $4-4.5K installed in my neighborhood. A pair of 3/4 ton or a 3/4 + 1 ton would run about 5-6 grand, as would a 1.5 to 2-ton 2-head multi split. YMMV. The hardware is actually pretty cheap, and most of the installation can be DIY, if you read up on it. Pay attention to "lowest operating temperature" in the specs- some go much lower than others. Most are still running at temps lower than specified, but with unrated/unspecified output & efficiency at lower temps. (The Mitsu GExx don't go as cold as the FExx, the Fuji RLX don't go as cold as RLS2, which doesn't go as low as the RLS2-H, etc.) Think seriously about your lowest temps of the past decade, as well as the 99% outside design temp when selecting a mini-split if it's going to be your primary source of heat.
The more rooms you can heat with the mini-split, the better, since it averages over 3x the raw efficiency of cove heaters or baseboards. Cove heaters in the intermittent-use rooms that use occupancy sensors to automatically turn off when unoccupied work out pretty well for many, and uses far less power than just keeping the room at a comfortable temp with a thermostat-only approach to control. The rooms run colder, except when you're using them, and colder==lower heat loss, and heat conducted thorough the walls from the mini-split rooms will limit just HOW cold they get. It's often a good strategy to slightly overheat the space with the mini-split to ease comfort issues in doored off rooms, but with cove heaters reasonably sized, the fact that they're warming you directly even when the room is still way below the thermostat setpoint makes it reasonably comfortable- it's sort of like an "instant on" radiator- radiating heat at you within 15 seconds of entering the cool room- it might be only 55-60F, but it feels warmer while it's running- like standing in the sun on a cold winter day. Like anything else, the cove heaters have to be sized reasonably for their heat loads. There's little energy-use penalty for oversizing them, but at some level of oversizing makes you feel like you're in a broiler.
A common installation error in the northeast is to mount the exterior units where they can be buried in roof avalanches, crushed by falling ice dams, or choked by drifting snow. Bracket mounting it on an exterior wall protected by overhanging eaves or rake of the roof- under the rake is better, since cornice-fall & roof avalanches are pretty much eliminated) is the right approach, or at the very least an open shed roof extending at least a couple of feet on the sides and front of the exterior unit. (I know a guy who had do dig up a freshly installed Daikin twice this past season- despite being ground mounted under the eaves, with a too-small protective open-shed roof over it to boot.) It's not just an air conditioner- it needs to keep working during and after blizzards.
Running boiler on low temperature will cause condensation of vapor in the product of combustion, and along with sulfur will created acid environment at the gas side of the boiler and flue and chimney . So you can damage boiler permanently. Do not go below 140F on aquastat setting. Also consider legionella as well.
Thank you - looks like I have my work cut out for me this summer on figuring out what to do and how.
Would replacing the oil burner with gas be a viable option?
I know natural gas is cheap now, but who knows how long that will last.
I have the gas line on the adjacent street to the property and I was told I could bring it in - about 50 ft. of trenching and pipe installation.
Plus the cost of a new gas fired heater. Seems like an investment that would take many years to recoup.
[QUOTE=Dana;382726]Mitsubishi, Fujitsu, and Daikin together own something like 3/4 of the market in the US, with Mitsubishi the clear sales leader (if not necessarily the efficiency or innovation leader.) If you stick with any of those three you will probably have multiple levels of technical support & expertise. What you're looking for is a good HVAC contractor to advise on ductless mini-splits- there are many good mini-splits, not quite as many good HVAC contractors.
If you have a gas main on your street the a new 82% gas-fired steam boiler would have about the same cost about the same as running mini-splits, but the installed cost of a replacement boiler would likely be higher than pair of mini-splits, even without the additional cost of the in-ground gas plumbing. A gas-burner retrofit on the existing boiler would work, but it's efficiency would be much lower, and the operating costs higher.
What genanady says about condensation is true- firing the oil-boiler at under 140F results in acidic condensation in the flue & heat exchangers, shortening it's service life. (But it's already gone 2x what's considered a reasonable service life for a boiler.)
The bit about legionella is moot, since you're not even using the hot water coil. But even if you WERE using the coil it wouldn't be valid. Unlike tank heaters, tankless coils purge 100% of the water in the coil on (almost) every draw of hot water (except for very short-burst rinses), making the odds of getting a legionella colony started astronomically remote. Even in that one in a gazillion shot, the first time the boiler hits 160F during the heating season it the colony would be reliably dead in minutes. Legionella in hot water systems operated at too-low a temperature is 99.999% a tank storage temp issue, never a tankless issue. Tankless coils & standalone tankless hot water heaters do not stagnate volumes of water, and tankless coils in steam boilers get cooked to well over the kill temp of legionella many times per year.