Garn placement feasibility

[SolarAndWood]

I have a lower level walkout that I am considering sliding a 1500 into. I will be able to back the trailer right up to the outside wall. A few issues:

1. The header height I will have to slide under is 78". I can take one of the 2x8s off the plate to buy an inch and a half. Is this enough?

2. The horizontal vent will go under the floor of the porch. The floor is 10' above grade. This a problem?

3. The ceiling in the lower level is only 7' 2". Is this enough or will I have to cut a hole in the floor above to access the hatch? Not the end of the world but not real desirable.

It would be placed in one end of a 40x22 room. I am wondering if I can use the Garn as a radiator for this space? I am thinking that I would insulate on all sides/top except the one facing the room. Then, have a removable spray foam panel that would be in place when I don't want heat in the space. Has anyone tried this?

Thanks for the feedback.

 

[jebatty]

I know nothing about the Garn, but off-hand using it as a radiator should work well. I heat my 20 x 40 shop with a Tarm gasser installed in the shop, along with 1000 gal LP tank pressurized storage. The LP tank acts as a radiator and is the only heat source I need for the shop: no fans, pumps, etc., just the circ when the boiler is firing. I wrapped the tank with 6" of regular kraft-faced fiberglass, leaving about 4' exposed, and setup so I can remove another 2' of insulation as needed. The tank is 19' long. Works very well.

 

[SolarAndWood]

Thanks Jim, simpler is usually better. It sounds like I wouldn't have to leave as much as I was thinking exposed. However, if I go with a small boiler with an LP tank, I can achieve the same thing so the cost difference is 0 on this point.

 

[Jim K in PA]

I have a lower level walkout that I am considering sliding a 1500 into. I will be able to back the trailer right up to the outside wall. A few issues:

1. The header height I will have to slide under is 78". I can take one of the 2x8s off the plate to buy an inch and a half. Is this enough?

I was able to squeeze mine in an even shorter space, so as long as you are able to go in nearly level, you should be fine. Check out the pics on my site.

2. The horizontal vent will go under the floor of the porch. The floor is 10' above grade. This a problem?

It may be. The GARN flue is about 4' above floor level, so it would only be 6' below the porch floor. I would add horizontal piping to get it to discharge out past the porch. How far is the edge of the porch from where the GARN flue exits the building?

3. The ceiling in the lower level is only 7' 2". Is this enough or will I have to cut a hole in the floor above to access the hatch? Not the end of the world but not real desirable.

You will have to have some sort of access hatch. The GARN lid has the low water cutoff switch mounted to the center of it, so if you stay with the OEM configuration, you will need about 18" of clear height to get it on/off with the switch attached. Check out my pics to see how my hatch is configured.

It would be placed in one end of a 40x22 room. I am wondering if I can use the Garn as a radiator for this space? I am thinking that I would insulate on all sides/top except the one facing the room. Then, have a removable spray foam panel that would be in place when I don't want heat in the space. Has anyone tried this?

Thanks for the feedback.

I think you will find the room TOO warm with an entire side exposed. I am sure you can find a reasonable configuration that will keep the space comfortable. Perhaps a couple of chases with convection from a floor level intake and upper level discharge, or add a fan and move the air to where you want it.

Keep us posted!

 

[SolarAndWood]

It may be. The GARN flue is about 4' above floor level, so it would only be 6' below the porch floor. I would add horizontal piping to get it to discharge out past the porch. How far is the edge of the porch from where the GARN flue exits the building?

The porch floor extends 7.5' from the wall. The porch roof, 22 feet off the ground, extends just under 9' from the wall. I designed large overhangs both for summer shading and to eliminate the need for gutters. If I run the vent beyond the roof overhang, I will have snow sliding off a 12/12 pitch roof with up to 35' to accelerate before it hits the vent.

I have always liked the Garn but every placement I came up with before this one required construction and dealing with pipes in the ground or in unheated potentially frozen spaces. As I was laying out the footers for the porch last week, it occurred to me that I could slide it right in where I put a big header in for a pair of 4' wide windows. Not that big of a deal given that the siding isn't up yet and the mechanicals are not even started. Once I find a way to make it work in the lower level, a Garn becomes a much more viable option.

I also like the idea of a big radiator in the lower level. In the even of an extended power failure, I only need to keep the boiler running to keep the whole house warm.

 

[pybyr]

If the Garn will be in a 40x22 ft room, is there any possibility of turning it 90 degrees so that the vent need not exit under the porch? I guess that will depend on whether either of the other walls around the corner from the porch have any above-grade area. I don't have a Garn, and any of these varying technologies have their pros and cons, but a Garn in the basement would be an excellent arrangement, for the precise reasons you mention.

 

[SolarAndWood]

I only excavated the SW side of the house down to the slab. The porch extends the whole length of the house on the SW side. I didn't want to add on to the house, so a little excavation and 9 4' x 5' windows bought me some relatively cheap naturally lit living space with a nice view. The porch will extend the living space as well as we spend a lot of our time outside. As an added bonus, the excavated material turned into the first garden terrace.

 

[Jim K in PA]

Can you put in a 90 under the porch and let it discharge to the side of the porch and roof overhang?

 

[SolarAndWood]

On the lower level, the two windows next to the door on the right have a single header that goes across them. This is where the boiler would go through the wall. The porch extends on the main floor of the house from that block wall on the right all the way to the left end of the house. I think if the boiler sits there, the pipe either goes straight out or up through the roof.

Another alternative considered was to put the boiler under the other wing of the house. The far left end of the house on the side you see gets ripped off in another month or so, a new foundation dug and another set of trusses over the top. I think I have eliminated that option for the boiler room because of the complexity of the excavation and cost.

What is exiting the vent that I need to be concerned with under the porch floor? Is it a fire risk you are concerned with?

 

[Jim K in PA]

What is exiting the vent that I need to be concerned with under the porch floor? Is it a fire risk you are concerned with?

Flue gases from the GARN exit at anywhere from 250-350 degrees F. At start up and toward the end of the burn you can and will get some smoke/soot. During the burn you will get incandescent embers exiting the flue from time to time. Depending on moisture content, you will also get a fair amount of steam. Heat, sparks, CO, and soot would be my concerns.

Given that the flue is only 6" wide, I would still run it out past the end of the porch, and if need be, build a snow deflector. However, whether discharging under or at the edge of the porch, make sure the snow pile does not block flow and trap CO in a well near the house. You have a lot of windows there.


Cute little garden gnome you have there. She'll be able to load the GARN as soon as she is tall enough to reach the handle.

 

[Jim K in PA]

water condensation may freeze in extended pipe resulting in blockage?

Unlikely with a run under 20', as the flow rate in the GARN is very high, and the vapor phase is in the early to middle part of the burn.

 

[SolarAndWood]

Can you put in a 90 under the porch and let it discharge to the side of the porch and roof overhang?

Is a 90 legit? If it is and it can be done inside, I could slide the boiler in and then rotate it and back it in to that masonry room on the right. The vent would then come through the block wall near the corner of the house and only be exposed a few feet on the outside and beyond the overhang.

Its kind of funny, I have considered building my storage tank in that room for a while now. The room above it faces due solar south and is going to be where the garden starts happen. A nice big radiator underneath the floor would give the plants a nice head start.

 

[SolarAndWood]

That would also get me out of having to have a hole in the living room floor for the top access.

 

[SolarAndWood]

That room is also the perfect size that if I put 4 inches of foam on the walls, I could use it as a water-to-air heat exhanger. That would probably give the Garn gods agita.

 

[Jim K in PA]

Sounds like you found your solution. Call Jim S at GARN and bounce your idea off of him. You can add a 90 in the discharge run, just keep the run shorter. Sounds like you can do that.

 

[SolarAndWood]

Thanks for the ideas Jim. Not having to run a chimney to the roof or deal with storage makes the Garn a nice option in addition to its other strengths.

So, given that it will sit 10 feet or so from my yet to be placed manifold, my plumbing would be pretty simple?

 

[Jim K in PA]

Plumbing simplicity really has nothing to do with proximity to the manifold. Since you are referring to manifold(s), I am taking that to mean you are not going P/S?

 

[SolarAndWood]

I haven't even started researching the distribution side. I removed the old propane forced air funace along with the ductwork, so starting from scratch. I am hoping to finish the shell of the building this year. I'd like to nail down the boiler/storage before I limit my options with siding/insulation/mechanicals/etc. Right now, the lower level is wide open.

 

[foxt]

Is a 90 legit?

I had the same question last Fall, and I wound up talking to Martin Lunde about it. His answer is "yes" (but maybe not for you - read on), you can execute a 90 with a Class A tee, but he had a few rules:

· The local inspector has final say on any project.
· You must have complete and continuous access to the tee for periodic cleaning - ie it cannot be buried in insulation, etc.
· The clean out cover of the tee is sealed, and resealed after each cleaning.
· The unit is not in a building where people are located.
· There is a 1' section of class A flue between the GARN unit and the tee.
· The tee and flue are full structurally supported utilizing metal (not wood or other combustible materials). A tee used in this configuration is not strong enough to support the flue connected to it.

Class A tees are made for non-pressurized outdoor installation as they will leak flue gas, including CO2 when used in pressurized flue applications. The GARN is a pressurized flue application.

If I understand your setup correctly, your install is inside a building where people are located, and given the concern about leaking flue gas, Martin would rule out the use of a tee ...

For what it is worth, I installed a tee on my unit, and despite sealing it well with silicone, I do think it still leaks a bit ...

Tom

 

[SolarAndWood]

Is a 90 legit?

I had the same question last Fall, and I wound up talking to Martin Lunde about it.

If I understand your setup correctly, your install is inside a building where people are located, and given the concern about leaking flue gas, Martin would rule out the use of a tee ...

For what it is worth, I installed a tee on my unit, and despite sealing it well with silicone, I do think it still leaks a bit ...

Tom

Thanks Tom, even though it would have been the ideal placement, the idea of the 90 in house didn't sit well with me. I came up with a solution to run it straight that I can live with, so the 1500 is still on the short list.