Tom's 12/27 unpressurized heating systems blog

[SolarAndWood]

I am intrigued by Tom's 5 paragraph tease of the simplicity of an unpressurized system. http://blog.americansolartechnics.com/2011/12/unpressurized-heating-systems.html

A couple basic ?s. I assume you need a non-pressurized boiler or a heat exchanger if you have an unpressurized tank? Are there other unpressurized gasifiers out there other than the Garn? How do you keep the water in the zones above tank level from ending up on the basement floor?

 

[maple1]

Both boiler & zones would be pressurized, each with a heat exchanger. Two separate systems, with the storage in between.

 

[SolarAndWood]

That is what I thought but:

"The beauty of these simple systems is that they only require a pump and do not use a heat exchanger."

 

[maple1]

OK - I should have read the blog first. That's something I have never seen around here. I would think the zone pump would need to be below water level to avoid loss of prime - although a check might avoid that, long as it remained tight. I'd also be worried about getting water to floor 2, but sounded like that was a non-concern. Non-pressurized also can raise corrosion concerns. I wouldn't mind reading more on it either.

 

[leaddog]

I am intrigued by Tom's 5 paragraph tease of the simplicity of an unpressurized system. http://blog.americansolartechnics.com/2011/12/unpressurized-heating-systems.html

A couple basic ?s. I assume you need a non-pressurized boiler or a heat exchanger if you have an unpressurized tank? Are there other unpressurized gasifiers out there other than the Garn? How do you keep the water in the zones above tank level from ending up on the basement floor?

I think that once you have water in the line and as long as you have no leaks and the return line is under water that the wt. of the water in the line going up would equal the wt. of the water in the return and all the pump would have to do is circulate. Now if you get a small leak that would allow air to get in than you would have to PUMP water up to the second floor and thru the return to get things working again.
Think syphoning. once you get the liquid flowing the wt of the liquid will keep the flow going.
Alot of OWB.s work this way. The boiler is lower outside and still pump water up into the house.
leaddog