First Post in the Boiler Room

Hi All,

First post over here in the boiler room. I've done some forum searching but haven't really come up with what I'm looking for.

First of all, I'm a total boiler novice. I understand that wood makes fire, fire heats water, water heats house. That's about it.

Here's the reason I'm posting. I have a vintage 1960's propane boiler in my house feeding radiant baseboard panels. Boiler is in working order, panels work, no leaks, etc. It is very capable of overheating the house (previous older couple living here kept the stat on 78*) so I have no concerns with sizing. HVAC friend says I should have no issue with them going "bad".

I don't think I need to go into detail about how expensive the propane boiler is to operate. I'm offsetting it considerably with a wood stove. Due to the layout of our house, heating with a stove is less than ideal in terms of heat distribution (long ranch house, closed floor plan).

Now I'm starting to think if I'm going to do all the work of heating with wood, I might as well have an even heat and a boiler would be a good option.

Ideally I would:
1.) Keep the old boiler for backup heat just in case we are out of town, boiler fails, whatever.
2.) Tie in the new outdoor boiler to the existing radiant heat system
3.) Tie in the new outdoor boiler to DHW and keep the current propane water heater for non-burning months
4.) Heat my shop with a ductless forced air setup

I have room for storage inside.

I guess my questions are:

1.) House + semi-finished basement = 3,400 sq ft. Shop is poorly insulated and ~1000sq ft...plan to insulated sometime....only would heat 2 days a week at most. What size boiler would I need?
2.) What is the best way to tie into the existing forced hot water system?
3.) How much storage would I need?
4.) I would like to do as much of the installation myself as possible. I'm sure it's harder than an oil change and easier than rocket surgery. I have plumbing and carpentry skills but am not much for electrical. How hard would this be to put in myself.
5.) What am I NOT thinking about?

I got a quote on upgrading the boiler. It was a lot. More than I would ever save on the increased efficiency. No ROI there.

Firewood is not a concern. I can get all I want for free and enjoy processing it.

Old boiler is 200K BTU and 50% efficiency is probably realistic.

ISeeDeadBTUs said:

Welcome to the Boiler Room, Virgin. Here, other people like to spend your money .

"don't just buy a solid fuel hydronic, get a new fossil one too . . .:

Anyway, you prolly won't use the fossil that much once you have wood up and running.

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Exactly. I know the boiler I have sucks and is probably too big. I don't need advice on it. I would like some feedback on my questions above. Please consider this a friendly redirect.

benjamin said:

200k?!? Would that be Barrow, Indiana?

You can get a pretty good guestimate of your heat loss by figuring that boiler puts out 100-150k btu and then go down there and time it for a little while when you get a cold night, like tonight. If it runs 20% of the time at 0 outside temp and that's your design temp then that gives you a pretty good place to start.

Obviously, if you want to burn wood you don't want to listen to how much sense it makes to get an efficient gas system instead, but it might. You may still want to think about weatherizing and insulating the house, so the wood cutting is more of a hobby and less of a second job. If the basement is insulated and if the existing boiler is closed off from the chimney, then you'd have less loss from the existing boiler, and may not even bother redoing that piping and controls.

Seriously 200k in a ranch in Indiana? that's oversized for most of the Victorians I see with any kind of air sealing.

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I know the boiler is oversized but don't have a good idea of how oversized. I'll take your advice into consideration about observing the run time on the coldest nights.

For some additional background info. The boiler is original to the 1960 house. Since the boiler was installed the basement has been partially insulated, insulation added to the attic, and all new windows (and there are several LARGE windows). The house is pretty tight now. I need to do some additional insulating in the attic but have some other remodeling projects I need to get done before I can do that (to avoid rework).

Como said:

Contractors tend to oversize Boiler, even now.

It would not have been that efficient 50 years ago and with age a lot more so.

My guess is that the actual peak load, with insulation improvements, is less than 100,000Btu's

Baseboard usually require very high temperatures to get its rated output, higher than a wood system may prefer.

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Current boiler runs up to 140* most of the time in short bursts, but will go to 180* under heavy load. What temp would wood system prefer?

I reread the quote for LP boiler replacement and it was spec'd at 120K input BTU per manual J calculation.

Como said:

If the guy did a Manaual J Calc you are at least heading in the right direction.

Find out what the Boiler efficiency rating is to see his view on net usage.

(If I ran 200 it would be steam heating)

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Works out to about 110K output BTU. This doesn't include my shop. No clue how many BTUS that would take. Moderately insulated 900 sq ft, heated sparingly.

djblech said:

Lukem,
Here is what I did. I installed a wood boiler in my garage (75' away) and ran a loop from there to a plate heat exchanger next to my propane boiler. This isolates my wood system so that if I need to shut it down the house is not without heat. Then I ran a loop through the propane boiler to the heat exchanger with 3 valves. When the 2 valves are opened and the one on the boiler shut the propane has to circulate through the heat exchanger. I just turn down the propane and let the wood carry the load. This works for me because I have 5 zones and a hot water maker. I am running 3 pumps on my wood boiler, 1 circulates through the boiler, 1 circulates the loop, and on is for a mixing loop at the boiler so that cold water does not shock my boiler. My propane boiler runs 2 pumps for circulation through my zones.
A couple of qualifiers. I am a carpenter, not a plumber. I understand this system but it is about at my limit. I do not have storage. I do not have a power failure back-up yet, working on it. I do have a dump zone loop in the garage and a generator sitting near the wood boiler. I have had to shovel out hot coals in Jan when the power failed. Boilers are a learning experience, 3rd year running this system and I am starting to get it right.
Doug

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This sounds like what I'm looking to do. I only have one zone inside the house with one circulation pump. I'm thinking I would need to have (based on no relevant knowledge or experience...please correct me where I'm wrong):

1.) Plate exchanger at DHW
2.) Plate exchanger at propane boiler (no idea how to plumb it into the existing lines)
3.) Circulation pump for loop from boiler, through plate exchangers, returning to boiler.
4.) Radiator in shop
5.) Circulation pump for loop from boiler, through radiator, returning to boiler.
6.) Thermostat in shop to control fan/air handler for radiator.
7.) Loop from shop radiator to boiler < 25'.
8.) Loop from house to boiler ~100'
9.) Control panel?

Where I'm still sketchy is how to cycle the water through the house radiators. Right now I have a very simple system where one thermostat lights boiler and turns circulator pump on...they always run pretty much together. I would assume I'd need a control panel of some sort to work in unison with the boiler (keeps propane from firing but still runs circulator). I want the propane to be an automatic backup...no intervention required.

Alright guys...where am I off?