Connecting wood boiler

[Quad4012]

Hello all,

I wanted to get everyone's opinion in regards to the heating system currently in our home. Little bit of background, we built our home approximately three years ago and are currently running a hearthstone equinox to heat our 1900 square-foot log cabin. Although I like the stove and its performance I would prefer the fire smoke and mess outside of the home. Within our home we have an open heating system where we draw water ( powered by an LP boiler) from our radiators and in floor radiant heat for domestic water. Being that we have baseboard on the second floor and in floor radiant on the entire first it is obviously mixed down to lower temperatures as our propane boiler is set at 175.

I have done quite a bit of research in regards to the outdoor wood gasification boilers. I really have my eye on the portage and Main unit but have also been eyeing a more local dealer who sells the G 200.

My plan was to simply install an outdoor boiler and utilize the heat through a heat exchanger plate. Here is my concern, looking at all of the boilers you typically run and chemical additive to help prevent corrosion within the system. This will obviously be separated by a exchange a plate to keep The chemically treated water within the boiler from entering the home. My concern is because we have an open system and the floors also serve to provide water for the domestic hot water in which we drink what risk is there if the heat exchanger plates failed? I was speaking to a local gentleman who heard of a farmer who utilized a boiler to provide water to his cattle and barn. Apparently several died when the heat exchanger plate failed and bypassed boiler treatment fluid into the barn.

Just curious what everyone's thoughts were on this? I spent quite a bit of time on the site and have never come across anything of the sort.

Thanks!

 

[huffdawg]

Your feed water should be isolated by a vacuum breaker or back flow preventer ,so you shouldn't get boiler water in your domestic supply at least on the cold water side.You could possible get a leak through your DHW coil , but if its an open system your domestic water should be a lot higher pressure than your boiler water which would cause your storage tank to fill up. I have a pressurized system, last fall my my dhw coil got a pin hole in it . This started to create high pressure in my boiler water it lifted the pressure relief a few times. Will be replacing the tank very soon.

 

[mike van]

Even your oil or gas fired boiler has a hx in it, so your tap water is not whats been circulating through your pipes for years. You're just adding another one in the loop. I wouldn't worry -

 

[Quad4012]

Even your oil or gas fired boiler has a hx in it, so your tap water is not whats been circulating through your pipes for years. You're just adding another one in the loop. I wouldn't worry -

Here is an image of the current system. The copper pipe that you see on the bottom of the image that enters the center of the boiler is the return feet from the house. The copper pipe exiting the left side of the boiler flows out where the first tee allows domestic hot water supply to go to the house. if you were to continue to follow that pipe to the left that breaks off to my four individual circulator pumps. When there is a load on the domestic hot water the water is pulled from the boiler into the house in the floor hydronic system is refilled using Coldwater from our well. I could be missing something as I've been wrong before! However it appears that there is no break in the water that we drink from our loops in the house. In fact I went ahead and shut off all zones of heat in the house and we had no domestic hot water.

 

[Quad4012]

Your feed water should be isolated by a vacuum breaker or back flow preventer ,so you shouldn't get boiler water in your domestic supply at least on the cold water side.You could possible get a leak through your DHW coil , but if its an open system your domestic water should be a lot higher pressure than your boiler water which would cause your storage tank to fill up. I have a pressurized system, last fall my my dhw coil got a pin hole in it . This started to create high pressure in my boiler water it lifted the pressure relief a few times. Will be replacing the tank very soon.

I have never heard of a vacuum breaker. I will do some more research on it. This is all relatively new to me although I'm relatively handy. I installed all of the new in floor radiant domestic hot water lines and circulator pumps for the new addition in our home. You do bring up a good point of the pressure within our system being at higher pressure than that with in the boiler. Currently our system is sitting at 45 psi. I believe that the portage and Main boilers are running ambient pressure. Thanks to both of you guys for any input, it's much appreciated.

 

[huffdawg]

 

[Quad4012]

View attachment 183134

Thank you! I will take a look into them now

 

[huffdawg]

Here is an image of the current system. The copper pipe that you see on the bottom of the image that enters the center of the boiler is the return feet from the house. The copper pipe exiting the left side of the boiler flows out where the first tee allows domestic hot water supply to go to the house. if you were to continue to follow that pipe to the left that breaks off to my four individual circulator pumps. When there is a load on the domestic hot water the water is pulled from the boiler into the house in the floor hydronic system is refilled using Coldwater from our well. I could be missing something as I've been wrong before! However it appears that there is no break in the water that we drink from our loops in the house. In fact I went ahead and shut off all zones of heat in the house and we had no domestic hot water.

i dont see an image

 

[Quad4012]

i dont see an image

Let me try this again.

 

[Quad4012]

Here is one of the flow

 

[velvetfoot]

I'm totally not an expert, but your current system is interesting to me.

I find it interesting that the water that flows through the baseboard and floors also comes out the hot water tap. Usually, it seems that the boiler water is closed or treated to discourage corrosion of the iron/steel boiler, but maybe in your case the boiler is stainless steel so that is not a factor. I imagine that your circulating pumps are also of potable water design. Does it act as an instant on water heater in the summertime? It's pretty nice that you're not maintaining a hot tank.

I believe there is non-toxic propylene glycol antifreeze available for the outdoor boiler and its lines.

I think it would take a whole lot of smoke and mess to make it worthwhile to spend all the money and effort and hassle it would take to install that boiler, tie it in to your sweet system, make sure the domestic hot water works right, and operate and maintain it. If the inside smoke with the Hearthstone is bad, perhaps that can be addressed?

Have you made sure that with all the newish NYS DEC regulations it'll be possible to site it? I think there are setback and stack height requirements as well as having the boiler be on a DEC list. I also think with an OWB with no storage there'll be more smoking at low-load even if it is on the list and it'll use more wood because of the heat losses.

 

[maple1]

I haven't seen a system that mixes DHW & system water, and not sure it's a good idea. They should have distinctly different pressure requirements, for one thing.

Are you SURE about what you've said about that? If so, I am quite sure I would make changes & separate them. Just generally sounds like bad news - also suspecting a code issue of some sort with it. But not sure.

EDIT: Your diagram shows an in & out of the boiler, 2 connections - but in the pic I think I see 4 connecting pipes on the bottom of the boiler?

 

[Quad4012]

I haven't seen a system that mixes DHW & system water, and not sure it's a good idea. They should have distinctly different pressure requirements, for one thing.

Are you SURE about what you've said about that? If so, I am quite sure I would make changes & separate them. Just generally sounds like bad news - also suspecting a code issue of some sort with it. But not sure.

EDIT: Your diagram shows an in & out of the boiler, 2 connections - but in the pic I think I see 4 connecting pipes on the bottom of the boiler?

I personally have never seen it either, the house was built three years ago and was supposedly inspected by the local building inspector. The system definitely draws hot water from the in floor radiant , If I shut off the zones I lose the Domestic hot water. The four lines coming out of the bottom of the boiler are for water in and water out, as well as overflow for pressure release and the fourth is for the propane input. It's a totally on-demand system and it works relatively well. It just makes no sense to me as why you would be consistently in putting fresh corrosive water into the entire heating system of the home.

 

[Quad4012]

I'm totally not an expert, but your current system is interesting to me.

I find it interesting that the water that flows through the baseboard and floors also comes out the hot water tap. Usually, it seems that the boiler water is closed or treated to discourage corrosion of the iron/steel boiler, but maybe in your case the boiler is stainless steel so that is not a factor. I imagine that your circulating pumps are also of potable water design. Does it act as an instant on water heater in the summertime? It's pretty nice that you're not maintaining a hot tank.

I believe there is non-toxic propylene glycol antifreeze available for the outdoor boiler and its lines.

I think it would take a whole lot of smoke and mess to make it worthwhile to spend all the money and effort and hassle it would take to install that boiler, tie it in to your sweet system, make sure the domestic hot water works right, and operate and maintain it. If the inside smoke with the Hearthstone is bad, perhaps that can be addressed?

Have you made sure that with all the newish NYS DEC regulations it'll be possible to site it? I think there are setback and stack height requirements as well as having the boiler be on a DEC list. I also think with an OWB with no storage there'll be more smoking at low-load even if it is on the list and it'll use more wood because of the heat losses.

Hearthstone does work relatively well. Keep your house warm but I am not a fan of having the mess along with loading several times a day. Not to mention we have a 14 month at home and it would be nice to get everything outside. i'm not really concerned about freezing of the boiler as my job is stable enough where I can be home every day to feed it and we can generally don't take any trips away during the winter. My concern is the toxic boiler treatment that would be placed into the boiler. The system works I just don't know why you were constantly putting corrosive water into the entire heating system of the home.

 

[velvetfoot]

The system works I just don't know why you were constantly putting corrosive water into the entire heating system of the home.

I just meant that fresh (oxygen containing) water is corrosive to iron, and the water inside a pressurized heating loop, not as much. You're constantly introducing fresh water for domestic water, and my theory why this is working out is because the boiler is stainless.

Even if you don't go anywhere, even for the entire winter, if the boiler craps out, say a control board takes a lightning hit, or a circulator fails and you don't have a spare. I guess if you're home you can do a generator if the power fails.

As I said, they apparently make non-toxic antifreeze. for example: https://www.amazon.com/dp/B004804N7E/?tag=hearthamazon-20

 

[maple1]

I personally have never seen it either, the house was built three years ago and was supposedly inspected by the local building inspector. The system definitely draws hot water from the in floor radiant , If I shut off the zones I lose the Domestic hot water. The four lines coming out of the bottom of the boiler are for water in and water out, as well as overflow for pressure release and the fourth is for the propane input. It's a totally on-demand system and it works relatively well. It just makes no sense to me as why you would be consistently in putting fresh corrosive water into the entire heating system of the home.

So how do you get DHW, in the non-heating months?

 

[velvetfoot]

It serves as a tankless water heater, I believe.

 

[Quad4012]

So how do you get DHW, in the non-heating months?

I can get to domestic hot water anytime. It just pulls water out of the in floor system. The system is then replaced by Cold well water. The way this is set up if I am taking a hot shower in the middle of the winter there is cold water bypassing the heater and entering the floor. So theoretically the floor cools down while any domestic hot water demand is present. Makes no real sense to me.

 

[Quad4012]

It serves as a tankless water heater, I believe.

That is correct. It's totally on demand

 

[Quad4012]

I just meant that fresh (oxygen containing) water is corrosive to iron, and the water inside a pressurized heating loop, not as much. You're constantly introducing fresh water for domestic water, and my theory why this is working out is because the boiler is stainless.

Even if you don't go anywhere, even for the entire winter, if the boiler craps out, say a control board takes a lightning hit, or a circulator fails and you don't have a spare. I guess if you're home you can do a generator if the power fails.

As I said, they apparently make non-toxic antifreeze. for example: https://www.amazon.com/dp/B004804N7E/?tag=hearthamazon-20

Do you have a home standby generator that I would eventually connect to the system. And I do agree that some anti-freeze is good freeze protection. Because it is non-toxic it was never really my concern. I'm just concerned about the boiler corrosion treatment which is generally toxic.

 

[velvetfoot]

boiler corrosion treatment which is generally toxic

Sorry, got it now.

 

[Quad4012]

Sorry, got it now.

No problem, I was just curious if anyone had any insight in regards to how to change our system to make it more boiler friendly.

 

[velvetfoot]

Perhaps if you broke out the manual for the boiler you have, it might have some suggestions for domestic hot water. Maybe there are connections on it for that, but you would think the plumber would use them then. I think my sister in law got a Bosch combi boiler that supplies hot water for heating and separate instant hot water personal use.

 

[huffdawg]

Perhaps if you broke out the manual for the boiler you have, it might have some suggestions for domestic hot water. Maybe there are connections on it for that, but you would think the plumber would use them then. I think my sister in law got a Bosch combi boiler that supplies hot water for heating and separate instant hot water personal use.

Ya you would think you could tee off before the floor loop somewhere for the dhw demand. Never heard of hot water running through your floors to get to your hot water tap. How hot is the water once it gets to the tap? Definately something I would change.

 

[Quad4012]

Ya you would think you could tee off before the floor loop somewhere for the dhw demand. Never heard of hot water running through your floors to get to your hot water tap. How hot is the water once it gets to the tap? Definately something I would change.

The water out of the tap is exceptionally fresh with no issues. Every time we take a shower completely replacing the water within the system so it's always fresh. I agree it needs to be changed