Outdoor/Underground Installation Possible for AA 130M?

I'm in the process of planning out my install of an AA 130, and after reading some threads here, I've opted against a garage installation.

So that got me thinking of alternatives. Opinions and suggestions are welcome...

First option: build small boiler-room structure detached from the house (see pic) out of concrete and cement blocks. Specs in the drawing are not going to be as precise as they are in the drawing.

Second option: dig pit next to house, pour pad, build block walls, or use pre-fab'd concrete box

- Ignoring local codes for now, how high does the chimney (or stovepipe) need to terminate above the shed's roofline? Is it relevant to the house being about 10 feet away?
- Should I pour an additional pad on top of plastic sheeting to elevate the boiler just an inch or two from any ground moisture that may wick up through the floor?

Is underground completely insane? An underground coal bin would be much easier to fill with my trailer, and I have a backhoe that can dig the hole and lower in the boiler no problem. Making it structurally safe is another question. It would need to support a vehicle, and not weaken the soil support of the house foundation. If I could solve those issues, underground is very appealing to me.

I'm not a builder, so I was going to pay/trade someone do the masonry work. I still haven't figured out how to cover the structures, either. Wood and shingles? Not sure how to cover it and still be able to fill the coal bin with a dump trailer.

Hey CoaledWinter,

Nice schematic!

Did you use Excel to draw that?

Standard codes read that chimneys must terminate 3 feet above the roof and 2 feet above anything within 10 feet of discharge. Check with the local building inspector.

Underground installation could be tricky if you are worried about the house foundation. Tempoary shoring may be required if you dig deep enough to under cut the foundation footer load line. Also, a traffic rated structure would be required if you want to drive onto it. Alot heavier structure and reinforcement would be required. Think $$$$$$$$$$$$$$$$$$$$$$$$$$$$.

For instance a standard two compartment 1500 gallon septic tank weighs 5213 lbs. A traffic rated 1500 gallon septic tank weighs 32,152 lbs. Now I realize that traffic rating is for usually H20 load ratings, which is truck traffic. But you should get the general idea of what it takes to handle a roof load on a underground structure.

Stick to a shed idea, it will be much more cost effective.

Steamup, holy cow... Yeah, I think I'll stick to above ground. Thanks for the info. Maybe I'll move it another foot from the house to avoid having a 20' stack over a 6' shed...

Mark, thanks. I used Microsoft Visio for that. I'd like to eventually get professional cad software, but Visio'll work for the simple stuff like this.

Well it's been a while, and I still haven't installed the boiler... I've been a little too busy, and it's way too easy to forget about boiler installation all summer. Although, it's been on my mind and I finally reassembled the unit a few months ago.

I just bought a 10'x8' shed, so I'll be installing it in that beside the house in the next month or so. Looking forward to bugging you guys with noob questions and spending some time browsing the forum to learn how to do this right...

We'll be looking forward to helping with your install, and your questions.
I have an AA260M in an outbuilding with insulated pipes burried underground going to both the house [150'] and the shop [150' the other direction]
My AA heats my DHW and a 4000sqft house and a 2400sqft shopfloor.

You will be very happy with your AA, once it is fired up and making heat.

Greg L

150' to the shop floor? That's awesome! I didn't even consider going that far from the house, I figured I had to be pretty close to not lose too many BTU's to the ground. I'm sure I saw a calculator either on here or an outdoor wood boiler vendor's site once, it made it look too inefficient to be where I wanted it (about 130' from the house).

It would definitely make life a lot easier to go that far, and I'd use it to heat my outbuilding instead of electric. The current oil fired boiler is a 140k, the AA is a 130.

CoaledWinter wrote:150' to the shop floor? That's awesome! I didn't even consider going that far from the house, I figured I had to be pretty close to not lose too many BTU's to the ground. I'm sure I saw a calculator either on here or an outdoor wood boiler vendor's site once, it made it look too inefficient to be where I wanted it (about 130' from the house).

It would definitely make life a lot easier to go that far, and I'd use it to heat my outbuilding instead of electric. The current oil fired boiler is a 140k, the AA is a 130.

To run distances like that, these guys will tell you requires insulating those underground pipes quite well. And also making them waterproof as ground water will suck heat out faster than anything else.

Rick

Rick 386 wrote:
To run distances like that, these guys will tell you requires insulating those underground pipes quite well. And also making them waterproof as ground water will suck heat out faster than anything else.

Rick

I here tell electric conduet burried underground will fill with water from condensation, I would think the same would apply to any pipes over time. Pitch the pipe and allow the pipe to drain off somewhere ???

a thermo pex, or insul pex is probably the way to go. I did alot of research before I did mine. I ended up buying thermo pex from a nearby outdoor wood boiler dealer. pricey, 13-15/ft for 1'' 18-22/ft for 1-1/4. burried 3 ft down well below frost line, there are new adapters out there that wont restrict flow I think they are called pro-pex. the expansion tool is expensive, try and find a supply house that sells em maybe theyl loan you the tool. good luck. I love having my boiler out in my garage.

I just did the math, it would be cost prohibitive to do it right now, but not in the future. Thanks for the numbers and plumbing suggestion though.

The temporary plan to get it firing this season is a 10' insulated container about 10' from the house. Pretty much a truck body. If it saves me the $2500 in oil that I'm hoping it will this winter, I'll re-invest the savings into a longer term plan. I know my wife doesn't want a big white box next to the house, so I have to sort of eek this through as temporary.

AA130FIREMAN wrote:

Rick 386 wrote:
To run distances like that, these guys will tell you requires insulating those underground pipes quite well. And also making them waterproof as ground water will suck heat out faster than anything else.

Rick

I here tell electric conduet burried underground will fill with water from condensation, I would think the same would apply to any pipes over time. Pitch the pipe and allow the pipe to drain off somewhere ???

I believe I remember Freddy writing about that. He had a tube in the underground pipe connected to a small pump. I think he then just sealed both ends of the pipe with spray foam and reported back that it was dry ever since. Best to check with him, cause my memory may not be dependable.

CoaledWinter wrote:I just did the math, it would be cost prohibitive to do it right now, but not in the future. Thanks for the numbers and plumbing suggestion though.

The temporary plan to get it firing this season is a 10' insulated container about 10' from the house. Pretty much a truck body. If it saves me the $2500 in oil that I'm hoping it will this winter, I'll re-invest the savings into a longer term plan. I know my wife doesn't want a big white box next to the house, so I have to sort of eek this through as temporary.

The key to acceptance of the big white box is the house must be at least 75 degrees shortly after you bring the AA online.

It is always painful to get started with a stoker boiler. Usually you are still bleeding from last years fuel oil bill, so setting the necessary funds aside can be tough. If putting the boiler in truck body allows you to get it online and set that money aside...that's what you need to do.

Rob R. wrote: If putting the boiler in truck body allows you to get it online and set that money aside...that's what you need to do.

I had something more "classy" in mind, but I guess an old van would work.