Could an outdoor boiler be used in a Hydronic floor system

[M Williams]

It just seems like this would be a match made in heaven.

I have no real world experience with either, but I can imagine the heat slowly radiating upwards from a radiant floor system would be cozy. Nice warm footsies

The outdoor boiler would be a no brainer for our situation as we have good burnable wood out the whazoo.

Thanks

[footer]

Yes......That would bet the ideal use for an outdoor boiler. Technically though, most are not boilers as they are open systems. Non pressurized.

[logwalker]

Why is it they don't seal the system. The advantage is with the sealed unit you don't get any appreciable corrosion. The available oxygen gets used up and is not replaced.

[Brian_Rhoad]

With a sealed system it must be tested and certified for pressure. If it is used for anything but residential you must have a certified boiler operater checking the boiler around the clock.

[jackpine]

My outdoor boiler , Aqua-Therm, is pressurized but only to 10 lbs, no more than an in-home hydronic heating system. At that low pressure I am not sure about the requirements for non-residential. The other advantage of pressurized systems is that the circulating pump can be smaller, esp if you have an uphill run.The disadvantage is that you have to monitor the pressure on startup in the fall because of the wide swing in pressure from cold water to 180 deg. water.

Bill

[beenthere]

Like Jackpine,
My indoor system is closed, but I've been told I can't buy another like it, because it now would have to be certified boiler etc.
Also told, that is the reason they are going to outdoor 'boilers' because they don't have to be certified.

But my indoor unit is no different than the 'gas' boiler that heats the water in a closed system, and runs about 12-14 psi. Have to degas the water to keep corrosion down (I do that by not admitting new water unless I heat it right away to drive off the oxygen), so I do not have an automatic filler. I just watch the water pressure and fill if necessary. Haven't touched it in 5 years.

So also am wondering why outdoor systems are not also closed.

[thecfarm]

Probaly it all boils down to money.I would bet it's easier,quicker and cheaper to build a open system than closed.May have something to do with liability,insurance. Which is money.

[Al]

Here in my part of Wisconsin infloor heat with an outdoor boiler is very very common.
In new construction with a boiler I'd guess more than 75% end up being used at least partially that way.
I have infloor heat in about half my home and it is indeed very cozy.
Gas boiler though, I'd rather do what I do for a living and earn the $1000 it costs for propane than spend that same amount  of time messing  with wood.

[jackpine]

One of the advantages of the open system is that they are much more forgiving on startup, you do not have to monitor the pressure because there is none. With the open system you can let the fire go out for a few days when it's warm and start it back up with no worries. They also hold much more water than a closed system so it takes much longer for it to cool down.

With the closed system the wide temp, range from cold to hot means that some air will get into the system on cooldown even if the system doesn't leak water,  it can leak air. On startup this air must be removed and, if fired up too quickly for the air bleed to do so, will cause an over pressure condition. While the system has overpressure protection, when it opens you lose water as well as the air and will not close until pressure drops to 0.

I think it is really a matter of personal choice on which type of system a person wants, but they should be informed of the differences before buying. In my case I wanted the pressurized system.

[Bill in U.P.]

I have both the OWB and in-floor heat in the basement. It really is the only way to go for heating a basement. I have the in-floor on a seperate system with a flat plate heat exch. and I put about 2-3lb. pressure in it. The floor right now is about 78 deg. In my old house just south of here, the basement wouldn't get over about 55deg. in the winter. This way I have a whole new living area to use year-round.

[maple flats]

I used to deal in outdoor wood "boilers". One of our bigger installs was a farm workshop with floor heat. It worked perfectly. As for pressure vs non, one difference is that non can not use antifreeze, because the antifreeze breaks down and the corrosion inhibitor evaporates away, so I was told. This leaves it unprotected. Most companies go non pressure because they do not have to have the technology nor testing to even market it in the first place. No pressure and you can just knock anything together, if pressurized you must provide specific certified test ing and meet specific industry safety guideline minimums. Most companies at least when i was in it had no engineering experts, just an idea and a welder. Newer ones seem to have some more design thought into them. It looks like a new generation of units has arrived even tho most are still no pressure.