Outdoor boiler / how they work

[Indiana wood]

Outdoor boiler question
When there is no call for heat does the boiler just maintain the desired water temp? Does the water circulate through the line set continually or does circulation start on a call for heat?

 

[salecker]

Hi
You can set one up pretty much anyway you like.
If you don't have storage with your boiler,then when there is no call for heat your boiler "Idles" which means the fire smolders away till there is a call for heat.Idling also causes creosote in your boiler which is bad.
The fluid most use is water,if so it always has to circulate.
I have antifreeze in my underground lines,but i have a pump that continuously runs for my underground lines.I have separate zones in my house that open when there is heat required.
My outdoor boiler is in it's own building,in that building is my 1000 gal storage,my backup oil boiler,storage for "DRY" wood,plus a heated workspace that is warm 24/7.
The way i have it set up i start a fire around 5 in the evening and my storage is full of heat by 11 when the boiler gets shut down till the next day around 5 again.Times vary with drops in temp.That is the average day in the winter at -20C.
125 ft walk to the boiler building which i don't mind.I get to enjoy my favorite smoke while there and work on a project in the warmth anytime i want during the winter.A full load lasts around 3 hours i like to reload around 2 1/2 hours.
No bugs,ash,dust,or smoke in my home.No flame sources,no carbon monoxide to worry about.
I live in a remote town with a volenteer fire department.Insurance costs are not affordable.My boiler building is my insurance.

 

[Indianawood]

The reason I ask is I picked up a old Hardy stainless steel boiler that stripped down. Currently I'm using it as an inground pool heater and it works wonderful. I currently burn wood in a blaze king. Ultra. I love the stove, but heating 5000 square feet requires 3 loads a day. So I was thinking of trying this Hardy boiler by modernizing it. I'd use an inkbird temperature controller. Which is Wi-Fi And has alarms high and low. I thought I'd set it at 1:45, maybe 165. Have it circulate all the time. That way all I have to do is figure out how to turn on my geothermal. Blower. When there's a call for heat. I would not be heating hot water. It has a storage capacity of about 100 gallons. It is an open system, not pressurized, so there's no risk of explosion. What do you think?

Hi
You can set one up pretty much anyway you like.
If you don't have storage with your boiler,then when there is no call for heat your boiler "Idles" which means the fire smolders away till there is a call for heat.Idling also causes creosote in your boiler which is bad.
The fluid most use is water,if so it always has to circulate.
I have antifreeze in my underground lines,but i have a pump that continuously runs for my underground lines.I have separate zones in my house that open when there is heat required.
My outdoor boiler is in it's own building,in that building is my 1000 gal storage,my backup oil boiler,storage for "DRY" wood,plus a heated workspace that is warm 24/7.
The way i have it set up i start a fire around 5 in the evening and my storage is full of heat by 11 when the boiler gets shut down till the next day around 5 again.Times vary with drops in temp.That is the average day in the winter at -20C.
125 ft walk to the boiler building which i don't mind.I get to enjoy my favorite smoke while there and work on a project in the warmth anytime i want during the winter.A full load lasts around 3 hours i like to reload around 2 1/2 hours.
No bugs,ash,dust,or smoke in my home.No flame sources,no carbon monoxide to worry about.
I live in a remote town with a volenteer fire department.Insurance costs are not affordable.My boiler building is my insurance.

 

[Indianawood]

The Inkbird controller would turn on and off the draft motor.

 

[E Yoder]

The ink bird control would work fine to send 120 v to the fan and solenoid. Run your pump all the time to prevent stratification and boiling issues. Hardy would have originally done a pump that only circulated on call for heat, but then it boils on a warm day.
Hardy didn't make real large wood boilers, 5000 sq ft might stretch it pretty hard, you'll have short burn times.
I'd do fan on at 160, off at 170. Maybe 180 in really cold weather. 145 is plenty low. You'll get more creosote.
I would guess your thermostat has a G terminal that starts the fan. Signal that with another thermostat and you should be good to go, occasionally on air source heat pumps some thermostats will backfeed and start the compressor. Then you need a relay to keep things separate.
This is unless it's a communicating system, then I'm lost. Ask your hvac guy what starts the fan.
Lots of old Hardy stoves around here in VA. They like to eat wood but they heat a lot of homes.
Best wishes.

 

[brenndatomu]

I currently burn wood in a blaze king. Ultra. I love the stove, but heating 5000 square feet requires 3 loads a day. So I was thinking of trying this Hardy boiler by modernizing it

You'll still need 2-3 (4?) loads per day (and larger ones at that) using the Hardy...you can make improvements in it by modernizing the controls, but you will still be stuck with that old school inefficient firebox design...

 

[Indianawood]

The ink bird control would work fine to send 120 v to the fan and solenoid. Run your pump all the time to prevent stratification and boiling issues. Hardy would have originally done a pump that only circulated on call for heat, but then it boils on a warm day.
Hardy didn't make real large wood boilers, 5000 sq ft might stretch it pretty hard, you'll have short burn times.
I'd do fan on at 160, off at 170. Maybe 180 in really cold weather. 145 is plenty low. You'll get more creosote.
I would guess your thermostat has a G terminal that starts the fan. Signal that with another thermostat and you should be good to go, occasionally on air source heat pumps some thermostats will backfeed and start the compressor. Then you need a relay to keep things separate.
This is unless it's a communicating system, then I'm lost. Ask your hvac guy what starts the fan.
Lots of old Hardy stoves around here in VA. They like to eat wood but they heat a lot of homes.
Best wishes.

Thank you for the information!

 

[Indianawood]

You'll still need 2-3 (4?) loads per day (and larger ones at that) using the Hardy...you can make improvements in it by modernizing the controls, but you will still be stuck with that old school inefficient firebox design...

Can you explain more? The hardy would be heating less square footage since it's not in the basement like the blaze king. The basement is 2500 square feet unfinished. The walls have 1.5" wall board insulation on them, something else i learned here. I know a lot of heat can be lost in the line set and insulation around the boiler.
With information i got here i was going to do the spray foam install method. I was also getting the highest r value insulation board i can find to reinsulate the original hardy cover. I was then going to put more on outside of unit.

 

[Indianawood]

Another question i had
The hardy has 3/4 pipe on back of stove. Do i need to run 1" line set? Or is 3/4" fine? It would seem 1" would be a waste unless i y onto 2 3/4 pipes.

 

[brenndatomu]

Can you explain more? The hardy would be heating less square footage since it's not in the basement like the blaze king. The basement is 2500 square feet unfinished. The walls have 1.5" wall board insulation on them, something else i learned here. I know a lot of heat can be lost in the line set and insulation around the boiler.
With information i got here i was going to do the spray foam install method. I was also getting the highest r value insulation board i can find to reinsulate the original hardy cover. I was then going to put more on outside of unit.

Just saying that they are pretty inefficient...and doing a proper OWB system can wrap up a bunch of money in a hurry (and almost limitless ways to screw up) then when you are all done you get to make wood like a fiend to keep up.
That BK stove is a good one...I'd probably tend to spend the money you'll spend on the OWB setup to insulate your basement better...or sell the BK and use that money to install a modern forced air wood furnace if you don't want the stove upstairs...26% tax credit available this year to buy and install a qualifying unit.
Just FYI, there is really only two units worth looking at...the Drolet Heat Commander, and the king of the hill, Kuuma Vaporfire 100.
My 2 cents...

 

[E Yoder]

Hardy used ¾" piping and outlets on the stove. Probably because that was common pex sizing in the south 25+ years ago. 1" will double your flow rate into the house and in most cases heat better. Then your only restrictions are the valves and 90 on the stove, not the whole line.
Hardy is one of the least efficient brands of outdoor boilers, it's just a square box with a chimney. Fairly reliable though. There are 3 brands of outdoor boilers that are eligible for the tax credit that I'm aware of, that will trim your cost down.
Burn time might not be as short as I thought if your area drops in half when you stop heating the basement.

 

[Indianawood]

Do i need glycol? Does the circulation pump keep things from freezing? Even without wood? Would i just drain it before leaving on a trip in the winter?
The Inkbird is working great! I have real time updates and alarms.

 

[Indianawood]

I only heat the basement now because i don't have a choice since the bk is in the basement

Hardy used ¾" piping and outlets on the stove. Probably because that was common pex sizing in the south 25+ years ago. 1" will double your flow rate into the house and in most cases heat better. Then your only restrictions are the valves and 90 on the stove, not the whole line.
Hardy is one of the least efficient brands of outdoor boilers, it's just a square box with a chimney. Fairly reliable though. There are 3 brands of outdoor boilers that are eligible for the tax credit that I'm aware of, that will trim your cost down.
Burn time might not be as short as I thought if your area drops in half when you stop heating the basement.

 

[salecker]

Myself...
I would not bother with an old inefficient water heater.
I would have been in the do it wrong a hundred different ways group if i had not come across Hearth.
most of what i was going to do i tossed out the window after reading on here for a couple months.
All that remained of my original plans was the building for a boiler and 1000 gallons of storage.
I decided to go with a boiler and closed system in the end instead of a water heater and an open system.
Weather your heating appliance is in the basement or not you will be heating the basement.

 

[Indianawood]

True but not to 80 degrees. Does the basement rob heat sure it does, but not 80 degrees worth when there is not a stove down there.

Myself...
I would not bother with an old inefficient water heater.
I would have been in the do it wrong a hundred different ways group if i had not come across Hearth.
most of what i was going to do i tossed out the window after reading on here for a couple months.
All that remained of my original plans was the building for a boiler and 1000 gallons of storage.
I decided to go with a boiler and closed system in the end instead of a water heater and an open system.
Weather your heating appliance is in the basement or not you will be heating the basement.

 

[andym]

Since you have the hardy and are familiar with it, why not go ahead and hook it up as you said. Just arrange and size everything so that you can easily swap in a new EPA outdoor boiler later. The tax credit will be lower, but isn't going to dissappear for several years.

 

[brenndatomu]

The tax credit will be lower, but isn't going to dissappear for several years.

Same this year and next, the drops a couple/three (4?) % for the 3rd year, then gone.

 

[Indianawood]

Since you have the hardy and are familiar with it, why not go ahead and hook it up as you said. Just arrange and size everything so that you can easily swap in a new EPA outdoor boiler later. The tax credit will be lower, but isn't going to dissappear for several years.

That's exactly what i am going to do. I love the simplicity of the set up. Easy to repair if necessary. I have unlimited firewood in my backyard 80 acres worth. Im gonna insulate the heck out of the lines and unit.
Although it will use more wood than the bk it doesn't have to be as perfect on moisture, length, diameter. A lot of time is spent cutting to 18" no longer, correct diameter, splitting, splitting, splitting
I also spend considerable time looking for only primo hardwood, with the Hardy who cares unless it's really cold.

 

[brenndatomu]

Although it will use more wood than the bk it doesn't have to be as perfect on moisture, length, diameter. A lot of time is spent cutting to 18" no longer, correct diameter, splitting, splitting, splitting

I think you underestimate how much more you'll use...and the whole "I can just throw anything in it" (wet, dry, split, unsplit etc.) is false economy...and irresponsible, unless maybe you live a couple miles from anybody else that has to deal with the smoke...but even then its still environmentally irresponsible. Nobody that I know locally that has an old school style boiler, like a Hardy, can "get ahead"...its just too much work/time for many/most to make 3 years worth of firewood when you are using 6-8 (more?) cords per year...and if its not dry, you are using 25%, probably more like 50% extra wood over what you would use with truly dry firewood. It might be fine at first, but unless you REALLY enjoy cutting wood, have all the extra free time to do it (and don't get hurt or ill...which is another benefit of being 3 years ahead...it takes the monkey off your back if you break a leg or something...) it will get to be more of a burden than a blessing after a while.
Member @hobbyheater posted some interesting stats here recently on his journey to a well designed boiler, and the benefits of using dry wood.
I agree with @andym , use the Hardy for now, but plan for doing an upgrade...

 

[Indianawood]

Thanks for the input. I agree im just getting my toes wet on the outdoor experience. No worries i plan on leaving the bk where its at so i can always fire it back up. It will definitely be a learning year. I am setting everything up so i czn easily go to a high efficient unit later.

I think you underestimate how much more you'll use...and the whole "I can just throw anything in it" (wet, dry, split, unsplit etc.) is false economy...and irresponsible, unless maybe you live a couple miles from anybody else that has to deal with the smoke...but even then its still environmentally irresponsible. Nobody that I know locally that has an old school style boiler, like a Hardy, can "get ahead"...its just too much work/time for many/most to make 3 years worth of firewood when you are using 6-8 (more?) cords per year...and if its not dry, you are using 25%, probably more like 50% extra wood over what you would use with truly dry firewood. It might be fine at first, but unless you REALLY enjoy cutting wood, have all the extra free time to do it (and don't get hurt or ill...which is another benefit of being 3 years ahead...it takes the monkey off your back if you break a leg or something...) it will get to be more of a burden than a blessing after a while.
Member @hobbyheater posted some interesting stats here recently on his journey to a well designed boiler, and the benefits of using dry wood.
I agree with @andym , use the Hardy for now, but plan for doing an upgrade...

 

[Indianawood]

How do i find the efficiency posts you refer too?[
QUOTE="brenndatomu, post: 2520060, member: 28195"]
I think you underestimate how much more you'll use...and the whole "I can just throw anything in it" (wet, dry, split, unsplit etc.) is false economy...and irresponsible, unless maybe you live a couple miles from anybody else that has to deal with the smoke...but even then its still environmentally irresponsible. Nobody that I know locally that has an old school style boiler, like a Hardy, can "get ahead"...its just too much work/time for many/most to make 3 years worth of firewood when you are using 6-8 (more?) cords per year...and if its not dry, you are using 25%, probably more like 50% extra wood over what you would use with truly dry firewood. It might be fine at first, but unless you REALLY enjoy cutting wood, have all the extra free time to do it (and don't get hurt or ill...which is another benefit of being 3 years ahead...it takes the monkey off your back if you break a leg or something...) it will get to be more of a burden than a blessing after a while.
Member @hobbyheater posted some interesting stats here recently on his journey to a well designed boiler, and the benefits of using dry wood.
I agree with @andym , use the Hardy for now, but plan for doing an upgrade...
[/QUOTE]

 

[brenndatomu]

How do i find the efficiency posts you refer too?[
QUOTE="brenndatomu, post: 2520060, member: 28195"]
I think you underestimate how much more you'll use...and the whole "I can just throw anything in it" (wet, dry, split, unsplit etc.) is false economy...and irresponsible, unless maybe you live a couple miles from anybody else that has to deal with the smoke...but even then its still environmentally irresponsible. Nobody that I know locally that has an old school style boiler, like a Hardy, can "get ahead"...its just too much work/time for many/most to make 3 years worth of firewood when you are using 6-8 (more?) cords per year...and if its not dry, you are using 25%, probably more like 50% extra wood over what you would use with truly dry firewood. It might be fine at first, but unless you REALLY enjoy cutting wood, have all the extra free time to do it (and don't get hurt or ill...which is another benefit of being 3 years ahead...it takes the monkey off your back if you break a leg or something...) it will get to be more of a burden than a blessing after a while.
Member @hobbyheater posted some interesting stats here recently on his journey to a well designed boiler, and the benefits of using dry wood.
I agree with @andym , use the Hardy for now, but plan for doing an upgrade...

[/QUOTE]

Boiler Progression

1981` we called it the pig it burned 22 cords in the only year we had it ! 1982 and 1983 the Tasso burned 16 cords a year without storage and 10 cords with ! 1984 to 2021 the Jetstream burned 3 1/2 to 4 1/2 cords per year. June 2021 Varmebaronen Vedolux 450 , what a clean boiler to light...

www.hearth.com

 

[Indianawood]

From the research I've been doing on here, it seems that the line set is very critical to be insulated well, so. You minimize heat loss. It would seem that the boiler itself would be. Also, a major concern for heat loss, since it's about 180 degrees And it's 20 degrees outside. I'm going to do a foam in place. Lineset why couldn't I put the cover on the Hardy and spray foam inside of that? Since new boilers are spray foamed I assume that's the best R value per inch. I understand I wouldn't be able to get the cover back off. But from my research, most leaks occur in the firebox area, not on the outside of the unit. Keep in mind this unit was $200, so I can't really hurt it. It's probably scrapped when I'm done with it.

 

[E Yoder]

I've seen a Hardy crack on the outside water jacket, it's thinner than the firebox. But it very much depends on the brand and how it's made.

 

[Indianawood]

Question of the day
Would it be any benifit to get rid of the grate and fire brick the bottom? Direct the draft either up the back or front of the unit. It seems most wood stove do not have grates, even an old bk i used to have.