Investigating replacing my oil boiler

We got our hands dirty last year with coal for the first time replacing our wood stove with a harman mark II and enjoyed warm toasty winter morning with much less effort. However, we still spend a fair amount on oil as our tankless hot water tank is part of the oil boiler and we have to heat a zone in an inlaw apartment to keep pipes from freezing. Ideally a new coal boiler in series or parallel would be ideal, but we have a small basement with little room leftover after the oil tank, boiler, electrical service, sump pump, and electric hot water heater for the inlaw apartment. We also only have one flue in the basement and no good location that I can see to power vent anything (i.e.: windows above only exterior walls to basement)

Our current boiler came with the house. It is a Burnham V-35.
http://www.hvacprotech.org/Firedragon/v3.pdf

From what I gather 208k btu/hr net.

So given my current circumstances I think that leaves me looking for a dual fuel unit as I think we need oil for code/insurance/resale value and we need the flexibility to head south during the winter for a vacation and not worry about the care and feeding of a coal unit. I was initially reluctant to go down this road, but it looks like the switchover from oil-coal-oil is relatively easy and doesn't require a licensed plumber to do it.

A local guy had me look at the LL WL110 but it looks like it doesn't have enough net output...or do I need to be looking at apples to apples with a coal unit? During our phone call he talked about the efficiencies of a coal boiler running all the time versus a oil fired unit having to "come on strong" to heat up on demand. Does this make any sense or should I be looking to match BTU for BTU with my current oil boiler?

The EFM 520 seems to come close on the coal side but the oil fired specs are too low. Can that be upgraded?

Can you point me in a direction of which models make sense for me to look at? On another note the height of the unit could be an issue also...We only have about 6' in the basement and with pipes running overhead even less. Occasional pooling of water in the basement also. The current boiler is on blocks and the new ones should also be. Even when the sump pump is working we get some pooling. When they fail...alot.

Thanks!!

frank33v wrote:The EFM 520 seems to come close on the coal side but the oil fired specs are too low. Can that be upgraded?

If you just need oil for times you are away you wont need to keep the house at 70° it may have more than enough btu s to keep the house at around 50° for those times.

Just a thought.

gaw wrote:

frank33v wrote:The EFM 520 seems to come close on the coal side but the oil fired specs are too low. Can that be upgraded?

If you just need oil for times you are away you wont need to keep the house at 70° it may have more than enough btu s to keep the house at around 50° for those times.

Just a thought.

Thanks, Yes that thought did cross my mind. But for re-sale value and the "who knows what can happen" scenario, I want to be able to run the house comfortably on oil also.

frank, just because your existing boiler is 200k btu's/hr doesn't mean that is the size required to do the job. My house has a 250k btu oil boiler in it, and yet I heat it at 72 degrees all winter long with an EFM 520 set at ~100k btu's/hr. Right before I installed the EFM I put an hour meter on the oil burner, and quickly discovered it rarely ran 30 minutes per hour even on cold days...so we can conclude it was double the size it needed to be.

Rather than just replacing what is there with something the same size, do a little research and see if the boiler really needs to have that much output.

How much fuel oil and coal did you burn last year?

Frank, as Rob has just stated, you probably don't need 200K in a solid fuel appliance, however, you are tight on space, and dual fuel is NOT an option I recommend from any manufacturer. That is more than a personal opinion, and I am well aware of the insurance regs, and certainly the real estate resale concerns. I can show you 9 dual fuel installs that have only had the burner on to test-fire it. The owners are sooooo happy with the coal that they do not even have the burners installed right now. Yes, they are available for Ins and/or real estate compliance, but that's it. 7 of the 9 burn 24-7/365. My $.02 from the peanut gallery.

Thanks for the replies. I figured the only way to answer this question was to go back through my records and see what we have done in oil that past few years. We have historically kept the house cold in the winter and supplemented heat in the main living rooms with wood so I suspect *WE* do not need all those BTU's but am not sure how to figure out if that high a number of BTU's is typical for a house this size. I am thinking resale value here...

Going to go through our records tonight or in the next few days.Last year was pretty mild so we can't go by that. We used 3.8t of coal in our stove last year.

Doug: I hear you..but why do you NOT recommend a dual fuel boiler?...because most users are happy enough and coal is a better option and never use the oil burner after paying for it..or that the oil option is unreliable and/or not implemented well in the units you have seen? If a dual fuel boiler is not a viable option then a project like this (complete replacement of our oil burner) may not be viable for me. We have zero time to deal with coal in the warm/shoulder months and the only time we can vacation is in the winter so the boiler needs to be able to be left unattended at times.

What do you know, my oil company has my history online.

On average I burn 1000gallons of oil a year. Last year being mild and we added the coal stove I burned a little more than 500g + 3.8 tons of coal.

Looking at the fuel calculator I see that that means I used about 1000g x 138,690btu/unit = 138.7 Million BTU's over the year. Not sure how that helps me in boiler sizing though...15k btu/hr on average..but that's not worst case scenario.

I think it's reasonable to consider how hard the oil boiler had to work to keep your place warm, but I don't agree with the idea that you should be trying to "shrink" the boiler so that it's rated output "matches" the work the oil boiler actually has been doing. A few of my reasons are as follows:

- A bigger boiler generally has a bigger heat exchange area, and may well be more efficient - e.g., if the alternative is to run an EFM 520 flat out, I bet you'd produce the same heat with less coal if you were using a 700, which has 53% more heat exchange area;

- Coal quality is not uniform, and even trusted sources can provide marginal product. A boiler sized too close to the load has little if any margin for error;

- The boiler may not perform to specs at any given time due to, for example, ash buildup;

- DHW loads can be very substantial - a boiler sized only to the heating load may not keep up;

- One of those -20 deg days in January with a 35 mph wind is not a good time to learn the stuff in the fine print of most heat loss computations;

- If you have plans for future expansion or additional loads to cover, it may make sense to install and maintain some extra capacity; and,

- That's how the Dead Men did it.

I've been accused of trying to be able to heat my house "with the roof removed", and I guess it may look like that, but to me it's preferable to putting a lot of time, effort and expense into a tightly-sized system, only to find that it comes up short when you need it the most.

Mike

Pacowy wrote:I think it's reasonable to consider how hard the oil boiler had to work to keep your place warm, but I don't agree with the idea that you should be trying to "shrink" the boiler so that it's rated output "matches" the work the oil boiler actually has been doing.

The answer usually lies somewhere in-between. In my house the oil boiler was big enough to heat my house and the two neighbors down the street...in my dad's house, the existing oil boiler was slightly undersized. In each case, it was easy enough to adjust the feed rate on our EFM's to get good performance. I would never recommend that someone size a coal boiler right on the edge of the home's demand, but I do think it is worthwhile to evaluate what the existing oil boiler is doing before you make a decision.

Pacowy wrote:- DHW loads can be very substantial - a boiler sized only to the heating load may not keep up;

That is an excellent point, and a BIG issue with new homes. New homes usually have a lot rate of heat loss, and might have 3 or more bathrooms...whirlpool tub, two head shower, etc.

frank33v wrote:Doug: I hear you..but why do you NOT recommend a dual fuel boiler?...because most users are happy enough and coal is a better option and never use the oil burner after paying for it..or that the oil option is unreliable and/or not implemented well in the units you have seen? If a dual fuel boiler is not a viable option then a project like this (complete replacement of our oil burner) may not be viable for me. We have zero time to deal with coal in the warm/shoulder months and the only time we can vacation is in the winter so the boiler needs to be able to be left unattended at times.

The EFM and Keystoker dual fuel units were built and designed to be coal boilers and it is as though someone said “let’s make a place to mount an oil gun and we’ll have a dual fuel boiler” they are not very efficient as oil fired boilers and the change over from one fuel to another is not automatic.

Consider your choices carefully. Coal is cheaper but you must be willing to do a little work in exchange. With oil most people just keep the tank filled and have it cleaned and serviced once a year.

Thanks for the warnings. I understand the switchover is not automatic, but it appears to be quite simple. So long as code allows a homeowner to do it I am fine with this. How inefficient is the oil side? It would only be used for domestic hot water during warmer months. From say December through spring I would run on coal.

Not afraid of a little work to heat during the peak heating season. We grow vegetables for a living during the warmer months and don't have time to think never mind deal with coal during the summer season, hence the need for oil for our domestic hot water. We have typically supplemented our heating with wood, and as of last year a hand fired coal stove during the winter months so I am thinking a stoker for a boiler would actually be less work!

This might be all a mute point as I might now have issues with the flue that my chimney guy says are fine for oil but the inspector would have an issue with for a solid fuel....

You mentioned resale considerations in your desire to use a dual fuel boiler. If you are not planning on leaving any time soon, I would forget all about resale at this point. If and when the time comes, pull the coal boiler out and replace with a oil burner. Coal boilers hold their value very well, and oil boilers can be found use in great shape for a lot less. You will be many dollars ahead in the end even if you pay someone to do the install and put in a new unit just on the fuel savings.

Welcome to the forum and congrats on looking into coal as an option. Most people are too close minded to even consider it. I can understand your need for the combo with the oil burner for shoulder months and vacations and due to space and time constraints, it makes sense to me. To me those are the real issues, not the resale value because as stated above you could replace a coal only unit with an oil unit and be dollars ahead on the money saved over the years.

I had a Mark III hand fed for 20 years and just last year went to a stoker stove in the house. I was very pleased with the switch and it was less work for me than the hand fed. Like you are planning to, I use our propane furnace for the shoulder months and when we go away. Although the shoulder months are not as much an issue now with the stoker as it was with the hand fed. Since the stoker is thermostat controlled I don't cook us out as much as I did with the hand fed. We had our windowstats open quite often over the years!!

I'd be a little leery of the comment that your chimney won't work for solid fuels. It may be a stupid code issue though and you may not have much choice. He might be thinking wood rather than coal when he says that. What is the construction & size of the chimney?

frank33v wrote:We got our hands dirty last year with coal for the first time replacing our wood stove with a harman mark II and enjoyed warm toasty winter morning with much less effort. However, we still spend a fair amount on oil as our tankless hot water tank is part of the oil boiler and we have to heat a zone in an inlaw apartment to keep pipes from freezing. Ideally a new coal boiler in series or parallel would be ideal, but we have a small basement with little room leftover after the oil tank, boiler, electrical service, sump pump, and electric hot water heater for the inlaw apartment. We also only have one flue in the basement and no good location that I can see to power vent anything (i.e.: windows above only exterior walls to basement)


A local guy had me look at the LL WL110 but it looks like it doesn't have enough net output...or do I need to be looking at apples to apples with a coal unit? During our phone call he talked about the efficiencies of a coal boiler running all the time versus a oil fired unit having to "come on strong" to heat up on demand. Does this make any sense or should I be looking to match BTU for BTU with my current oil boiler?


Thanks!!

Just curious are you keeping the Harmon . I am asking because that would supplement the heat on the really cold days just in case the WL110 cant quite keep up ( it would easily make up for it and you will have some heat if the power fails). Even though I doubt it would be an issue but 1000 gals of oil used previously ave makes me not quite sure but it is close. On Oil the WL110 can be sized to 165kbtus and be 86% efficient on oil. Just my 2 cents. But it may be worth considering. But of coarse I am a little biased. LOL
Dave

titleist1 wrote:What is the construction & size of the chimney?

Not sure if I describe it properly but I will try. The liners are tera-cotta? and the outside is cinder block construction. I have three flues in one chimney. The center flue is a large 12x18 that comes down to a 4' opening for a large fireplace. I installed my Harmon here. The flue for the oil burner is directly next to this flue at the top of the chimney but then takes a turn to get around the wider opening at the top of the opening of my fireplace (firebox?)then continues next to the fireplace down to the basement. All of this is encased in cinder block and red brick in the living room and above the roof. The other flue goes to a thimble opening on the other side of my fireplace that could only be used for a small stove, not really applicable here.

There are I guess two issues with the oil flue. The chimney guy claims cracking at the top and he says also down below. I have a cap on the center flue which he suspects has been directing extra water down the other flues. (He offerred a multi-flue cap to fix this and a few hundred bucks to replace the top masonry liner pieces...perhaps this addresses his concern of code issues with the cracking visible from the top...I need to clarify with him)

The second issue which concerns me a little (not sure if it should..) is that last year when he cleaned the oil flue (first time we have ever had this done) he jabbed his brush through the wall of the liner where it bends around the fireplace flue. He claims it so brittle that it went right through. Now I have a hole between the two flues above the firebox that he said he could not reach to repair without dismantling the fireplace. He claims this is ok for oil but would require a liner for anything else..and he can't bend a liner around the larger fireplace flue so he would have to do major surgery to put it in, suggesting it go right through the fireplace and a new hole in the floor making the fireplace essentially unusable ever in the future. The small insert liner (10') that I installed for the Harmon Mark II extends beyond this hole so I think the coal stove is venting fine through the larger flue. He said the smaller flue for the oil furnace would draft better than the larger one so the oil furnace should draft properly through it's own flue rather than seeping through the hole into the larger flue.

I hope I described it properly...I know a picture would help but the fireplace plate is back on around the stove vent so the hole is not visible now without taking the whole thing apart.