Proper pipe/foundation hole sizing for future outdoor wood boiler

[stuntman]

I recently started supplementing heat to my home with a wood stove (last couple years). I am also in the process of building a shop and the idea of an outdoor boiler (someday) is intriguing. I have the opportunity to install a foundation sleeve that leads directly to my wood shack which is seemingly where an outdoor boiler may reside someday.

My first inclination was to run a Schedule 40 PVC liner all the way to my utility room to the shop. After trying to stick even 1" pex through a 2" 45degree conduit fitting, I quickly realized I likely need to simply pass the pex lines through the foundation wall and sweep them up through the floor. Then plan on running them to the utility room on the interior of the building, not underneath the slab. Is this the general conensus?

Trying to plan for this future use has led down to some "bottom of the iceberg" considerations. Do I run 1 set of lines, 2 sets of lines. 1" or 1.25". Do I run two sets of differing sizes. Do I do floor heat as well as forced air. What about hot water heaters... the list goes on.

Finally to the question, what size (and radius of bend) conduit should I put through the foundation and floor to make sure I don't come up short down the road:

Specs:
Building is 4000sq feet with in-floor radiant heat (pex loops).
Building has a second story which is also 4000sq feet and may have forced air HVAC
Building has a hot water heater
So if I throw the kitchen sink at it I would need radiant heat, a heat exchanger for the furnace/ac, and a heat exchanger for the hot water heater.

What can I do? Two 4" long sweep conduit elbows? One 6" 36" radius elbow? Do I run the pex inside of the corruagted pipe right up to the foundation then remove the corrugated pipe and run the pair inside of a 3" conduit elbow?

I appreciate any insight anyone is willing to share.

 

[salecker]

Personally i would plan on the boiler being in your shop with storage.
I built a dedicated building for my heating system,which at some point will get attached to my shop with hallway.
Now the boiler building is a 24/7 warm shop for me to work on saws.It was my finishing building when i was building my house,all the trim and doors and door frames were built and finished in the boiler building.

 

[jblnut]

I ran an 8" drain tile, the black flexible stuff, from the mech room in my shop out past the exterior wall when I built the shop. I located where I was going to have the pipe come in and dug a 6' deep trench with a nice slope to the bottom of it. I did the same thing in my house when that was built a few years back.

When the time came to put the boiler and it's stuff in I ran the insulated pipe through the 8" pipe. Lots of room to pull in without issue. I used the foam filled stuff with 1-1/4" lines inside it.

If you think you'll max out 1-1/4" lines you could run two 8" sleeves from the shop to the wood shed. The 8" pipe isn't all that expensive and you can't add one later on lol. I ran mine under the slab and into the mech room. Simple and clean.

I have a ton of pics of the install if you'd like me to dig them up.

 

[maple1]

What kind of distance are you talking?

 

[stuntman]

Well, so I am most concerned with how to get the tubing INTO the building. Yes, I could go up and inside the wall, but I am mostly concerned with what kind of pass through to put into the foundation. I see that a few vendors of wood boiler pipe that have two sets of lines put them in 5" drain tile pipe. So as jblnut said, you would probably need something like an 8" passthrough.
The distance from the wood boiler to the workshop is around 75ft. From the workshop wall to the utility room is another 40 feet plus going up the wall and back down. All in all, I don't see the whole circuit being more than 150' in a worse case scenario.

Thank you for the input thus far!

 

[maple1]

I would only use good proper piping. Closed cell insulated, e.g Thermopex. Which I would think would be a severe challenge to pull through a sleeve or pipe of any length. At that length I also think I would use 1-1/4". Most installs I have seen have guys just core drilling a hole thru the foundation. Which at first thought might seem to be a good thing to avoid but might be the best approach if you are uncertain it is something you would ever do? Or, just make/leave a hole just in the concrete when you pour, maybe 8" diameter, and leave it at that for now.

 

[maple1]

But I would also be one to do what I could to get the boiler inside the shop. Or inside a room inside the shop. And the winters wood.

 

[jblnut]

If you're worried about going through the foundation you could use electrical conduit on the exterior of the building to get inside. It'd be another few fittings on the pex lines but it does work. I helped a buddy put a pair of 1-1/4" lines into his shop through some 5" gray conduit. We dug a trench leading away from the shop the sloped nicely up towards the shop when it got close. The 5" conduit was large enough to slip over the rehau boiler pipes. We had a foot or so of the pipe/insulation/pex lines into the conduit and stripped the rest away so it was just pex lines going into an LB fitting. A short piece of 5" conduit went through the wall into the shop where it went into another 5" LB. He put the pex in conduit to the ceiling so it was more protected but you certainly don't have to of course.

After crimping fittings on, which was not pleasant in the conduit, we foamed everything down the pipe and through the wall into the building. He has in floor heat and didn't want to core though the floor so this was the best thing we could think of for his after the face install.

If it's a new install and the floor isn't there yet I'd do an 8" sleeve in a heartbeat. There were 4-5 of us here and I had two guys inside pulling on some mule tape and two guys outside pushing on the boiler line and we shoved/pulled it through 70ish feet of sleeve. I purchased a 4" Chinese finger trap looking deal with a loop at the end that we put on the pipe to hold it tight and that was money well spent !!

I ran out of 8" sleeve so I used 10' or so of 6" to go under the stove and it was damn near impossible. Good thing we were outside as I had to use the mini-ex to get it though lol.

Here is the boiler line going into an 8" sleeve. TONS of room for activities in there still lol

 

[brenndatomu]

Well, so I am most concerned with how to get the tubing INTO the building. Yes, I could go up and inside the wall, but I am mostly concerned with what kind of pass through to put into the foundation. I see that a few vendors of wood boiler pipe that have two sets of lines put them in 5" drain tile pipe. So as jblnut said, you would probably need something like an 8" passthrough.
The distance from the wood boiler to the workshop is around 75ft. From the workshop wall to the utility room is another 40 feet plus going up the wall and back down. All in all, I don't see the whole circuit being more than 150' in a worse case scenario.

Thank you for the input thus far!

To me the easiest/best way to go through the basement wall is to core a hole large enough to put a 6 or 8" PVC pipe (sleeve) through, then use hydraulic cement to seal it in place...when you put the boiler line through you use Fernco's to seal everything up then.

https://www.supplyhouse.com/Fernco-1056-86-8-x-6-Flexible-Coupling-Cast-Iron-or-PVC-to-Cast-Iron-or-PVC