Wood burner with in-floor heat

hot_rod

That load number helps.

Here is some reading and formulas for designing a mini tube injection system that Carl eluded to. It's a way to move a lot of energy with small diameter line IF you have a large ∆T to work with. You do!

Looks like you have some number crunching hydronic experience now So plug your numbers into the formula and see how you can accomplish this and salvage that undersized OWF tube.

I have used this technique on large shop slabs 20,000 square feet to supply a manifold in the center of a large building.

Here is an example of a custom mini tube injection manifold I installed, welded by Earthlee back in Ridge NY. Two small diameter pex lines at the top supply all those 3/4"radiant loops.


https://www.supplyht.com/articles/96238-minitube-distribution-systems

GroundUp

That's actually pretty standard practice for Central Boiler. I've been a part of at least 100 Central Boiler systems sold to the homeowner by a dealer and the story is always the same. That's how Central trains their dealers because they don't understand hydronics themselves. I've personally spoken with corporate over a system sold by a very reputable dealer with that same 6048 boiler 270 feet from a 9000 sq ft truck shop with 20ft ceilings and they sold him 1" underground which was already buried in the concrete before I became part of the job as well as an 007. When I confronted corporate about this, the response was, and I quote, "we recommend 1" Thermopex for all installations". I again explained the heat load and flow capabilities of 1" in a length like this, especially with a circ like that, and was met with nothing but a blank stare. That system now has a pair of PL36's pushing the building loop and a 15-58 running an injection loop in the boiler cabinet to keep return temps above 150 as a full heat call for that massive slab will pull the water down under 100 degrees from 175.

As for the radiant side, as long as you pipe that to perform correctly, the heat source is irrelevant.

hot_rod

GroundUp said:

That's actually pretty standard practice for Central Boiler. I've been a part of at least 100 Central Boiler systems sold to the homeowner by a dealer and the story is always the same. That's how Central trains their dealers because they don't understand hydronics themselves. I've personally spoken with corporate over a system sold by a very reputable dealer with that same 6048 boiler 270 feet from a 9000 sq ft truck shop with 20ft ceilings and they sold him 1" underground which was already buried in the concrete before I became part of the job as well as an 007. When I confronted corporate about this, the response was, and I quote, "we recommend 1" Thermopex for all installations". I again explained the heat load and flow capabilities of 1" in a length like this, especially with a circ like that, and was met with nothing but a blank stare. That system now has a pair of PL36's pushing the building loop and a 15-58 running an injection loop in the boiler cabinet to keep return temps above 150 as a full heat call for that massive slab will pull the water down under 100 degrees from 175.

As for the radiant side, as long as you pipe that to perform correctly, the heat source is irrelevant.

That is interesting about Central. I think they hired Siggy to put some manuals together and train staff and dealers years back.

I've yet to find any OWB brand that provides correct sizing info for the piping.

GroundUp

Crown Royal is the only one I've seen that has educated schematics in their manual. I know the owner of Crown personally and those guys actually know what they're doing when it comes to hydronics. Any meatball with a welder can melt steel together and fill it with water and market it as an outdoor boiler, but very very few dealers and manufacturers alike actually understand hydronics. Some of Central's schematics are pretty detailed and it wouldn't surprise me if Siggy was a part of them, but I'd have a hard time believing they were tested on the information if he provided some training. I've spoken to maybe 20-25 Central dealers over the years and I can only think of one that had even the slightest clue how to size a pump or pipe

gpjazz

I checked the materials which customer purchased for this job...
For the garage radiant side, he has a B&G NRF-25 circulator and for the outdoor wood burner side a B&G NRF-45 circulator. These pumps were selected by the distributor where he purchased everything

hot_rod

Read through this tech journal it will take you thru the steps to size a circulator or see what the NRF 45 is capable of. You need to add up every tube, valve, fitting, heat exchanger in the loop, see what the pressure drop is on the pump curve at various GPM flow rates. Look like 30' is about all you have at the top, shut off head.

Ideally you want to run in the middle 1/3 of the curve, looks like curve #9.
https://www.caleffi.com/sites/default/files/coll_attach_file/idronics_16_na_0.pdf

psb75

All I can add is that you are getting topnotch advice here--none better. You'd best heed what you are hearing. That underground component of long runs of 1" pipe is the common "Achilles' Heel" of OWB installs. You "touch" this system--you "own" it--unless you get a serious CYA agreement on paper.

GroundUp

The 25 is too small for the floor, you'll be outside of the usable part of the curve. It'll work, but poorly. The 45 is about as good as you're going to get for the OWB. I'd step the floor circ up to an NRF-36 if B&G is the weapon of choice