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FYI: that's not a gravity system. It's a hot water system.

I truly don't understand why you would want to go back, but you can add a wood burning boiler outside and see if you like that. You would require adding glycol in that case. That way you would maintain your oil backup. Remember, if you're not home, no one is feeding the fire.

For the pipes corroding part: it's a sealed system. Once the O2 is locked away, very little chemical reaction will occur. Eventually you'll form leaks, but that takes a significant time. Mineral buildup is a concern for open water systems, not closed ones like yours. Water treatment options extend the life of everything in the system even further.

Cheers!
 

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Discussion Starter #3
FYI: that's not a gravity system. It's a hot water system.
It's a pressurized system, now, but was a gravity system. I'd just have to open it back up and add a new gravity expansion tank in the attic to bring it back to gravity, if I'm not mistaking? But you're saying it's not worth it?
 

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First, its not worth it.
Second, your confused on a gravity system needing its expansion tank in the attic. When it doesn't. 1000s of gravity system had/have their expansion tanks in teh basement.
Third. You need to see if your insurance company will allow a wood boiler as the sole source of heat, along with the place that your mortgage is through(if your have a mortgage), and your city.
4. You will need someone to always check on your house when you go a way for more then a day, to make sure the wood boiler is still burning.

While gravity is a very comfortable heat, as its a constant heat, because its slow. You will have to learn how to control the fire for the best rate.

A tankless coil(coil in the boiler) would defeat most of the benefits of a wood fire gravity heating system. The water temp needs to be kept to hot.

Better off just adding a wood fired boiler out side, and use a flat plate heat exchanger so you don't need glycol in the oil fired boiler. And if you get tired of hassling with the wood, you still have the oil boiler to fall back on. Along with the fact, that homes with just a wood boiler for heat, don't sell well.

Also, where are you going to get rid of the ash from 3 or 4 cords of wood a year.
 

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Discussion Starter #5
First, its not worth it.
Second, your confused on a gravity system needing its expansion tank in the attic. When it doesn't. 1000s of gravity system had/have their expansion tanks in teh basement.
Third. You need to see if your insurance company will allow a wood boiler as the sole source of heat, along with the place that your mortgage is through(if your have a mortgage), and your city.
4. You will need someone to always check on your house when you go a way for more then a day, to make sure the wood boiler is still burning.

While gravity is a very comfortable heat, as its a constant heat, because its slow. You will have to learn how to control the fire for the best rate.

A tankless coil(coil in the boiler) would defeat most of the benefits of a wood fire gravity heating system. The water temp needs to be kept to hot.

Better off just adding a wood fired boiler out side, and use a flat plate heat exchanger so you don't need glycol in the oil fired boiler. And if you get tired of hassling with the wood, you still have the oil boiler to fall back on. Along with the fact, that homes with just a wood boiler for heat, don't sell well.

Also, where are you going to get rid of the ash from 3 or 4 cords of wood a year.
Ok, there used to be a tank in the attic at the top of the stairs. It was confirmed by a plumber, years ago, that it was the old expansion tank for the gravity system. I thought the expansion tank in a gravity system had to be at the top of the system, because the system is open. I know this heating system isn't as user friendly, but I'd like to learn the system and get good at running it. Now, if I did this, what would you recommend I do for domestic hot water? Gas or electric water heater? The ash, at least some of it, will be put on the lawn and garden. How much ash should I expect? (1300 sq. ft. house in the northeast)
 

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Just as many gravity systems were 'closed' systems with a compression tank in the basement (usually up between the floor joists). My folks' house had an expansion tank in the attic with an overflow thru the roof. These fell out of favor due to allowing air to mix with the system water in the open tank...so they moved it to the basement (also to prevent freezing), and to prevent excess oxygen from getting into the pipes and causing corrosion issues.

My house was built in 1914 and always had the tank in the basement. My parents house was built in 1896 and had it in the attic.

Remember, if you want to go gravity, you'll have to use full size tappings, usually 2 for supply and 2 for return...that's how most houses around here were originally set up. Provide as little resistance to flow as possible. And as constant a fire as you can...gravity systems work best with a long burning, continuous fire.
 

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Discussion Starter #7
Just as many gravity systems were 'closed' systems with a compression tank in the basement (usually up between the floor joists). My folks' house had an expansion tank in the attic with an overflow thru the roof. These fell out of favor due to allowing air to mix with the system water in the open tank...so they moved it to the basement (also to prevent freezing), and to prevent excess oxygen from getting into the pipes and causing corrosion issues.

My house was built in 1914 and always had the tank in the basement. My parents house was built in 1896 and had it in the attic.

Remember, if you want to go gravity, you'll have to use full size tappings, usually 2 for supply and 2 for return...that's how most houses around here were originally set up. Provide as little resistance to flow as possible. And as constant a fire as you can...gravity systems work best with a long burning, continuous fire.
so I can have a gravity system that is also pressurized?
 

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Ayuh,... Donno why yer so bent on goin' to a gravity system,....

Leave it a pressurized system, 'n add yer wood boiler, through a heat exchanger,....
I'd also keep the heatmate DHW, 'n run it off the exchanger,...
You could run it on oil, or wood durin' the warmer months,...

If legal in yer area, an outdoor boiler makes the most sense, as if ya do a boiler in the cellar, the whole cellar will become yer woodshed,....
You'll be draggin' all the dirt, waste, sawdust, bugs, 'n critters into yer house,...
An outdoor boiler keeps all that, Outdoors,....

Myself, I built my own outdoor wood boiler, 'n plumbed it directly into the house hydronics,....
The whole system runs pressurized,....
 

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Discussion Starter #9
Ayuh,... Donno why yer so bent on goin' to a gravity system,....

Leave it a pressurized system, 'n add yer wood boiler, through a heat exchanger,....
I'd also keep the heatmate DHW, 'n run it off the exchanger,...
You could run it on oil, or wood durin' the warmer months,...

If legal in yer area, an outdoor boiler makes the most sense, as if ya do a boiler in the cellar, the whole cellar will become yer woodshed,....
You'll be draggin' all the dirt, waste, sawdust, bugs, 'n critters into yer house,...
An outdoor boiler keeps all that, Outdoors,....

Myself, I built my own outdoor wood boiler, 'n plumbed it directly into the house hydronics,....
The whole system runs pressurized,....
I'm not necessarily bent on making it a gravity system, it's just, if it were, I'd have heat eve when the power's out. (no, I don't want to deal with a generator) But maybe a wood stove is a better option.
 

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Discussion Starter #10
thoughts?

Anyways, there is a fireplace on the first floor. If not a wood stove or insert, is there any way to run a vent for outside air to get directly to the fireplace, so that cold air isn't sucked into the house, all around the house? This way, I leave the pressurized oil heating system alone and still have the ease of use of that, but have a way of heating the house when the power goes out and possibly have a cheaper way of heating at least the first floor during cold winter days?
 

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No easy way to put an outside combustion air intake to a fireplace that wasn't built with it.
 
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