Wood oil combination boiler

[Martin Reece]

Good day all,
I recently installed a wood , oil combination boiler. For the past 23 years I have heated with a wood stove with a backup oil boiler.
I was getting tired of the breezeway being way to warm, the living comfortable , the bathroom cold etc,etc.
I can't believe how well this thing works. It also heats my domestic hot water. Now the whole house is the same temperature.
Was just wondering if anyone else has a wood boiler?
thanks Martin:msp_thumbup:

 

[pdqdl]

Are you referring to a wood-fired hot water heating system? Nope, don't know of any.

I am rather interested in hearing about how yours works, though. When I was young, I lived in a hot water heated house, and it was the most comfortable type of heat I have ever lived in. Wood fired seems like an easy addition to an oil fired system.

Someday, I hope to convert my house to a hot-water heating system, and I intend to add woodburning capacity.
Tell us more!

questions perhaps to answer:

You mentioned a "boiler", but surely you are just using hot water. Boilers are pretty dangerous, and generally only found in really old systems.

Do you have automated controls to limit the wood fired system exchange to the main system, or is it manually switched?

Do you have zone controls for each of the rooms, or is everything on a full circulation loop?

Does the hot-water heat use the same water system, or is there just a heat exchanger between the oil fired system?

 

[PEKS]

Martin, post a few pics of your Boiler when you have a chance..
Let us see what you are using..
Cheers..

 

[Big L]

Really depends on the home. We reach extreme comfort here with just a wood stove. It's an open cube, a small 2 story colonial, about 1200ft² with a foot print of about 24' x 26' with 7'-2" ceilings. Comfy :msp_biggrin: Good airflow. Do have a backup oil fired hot water loop on one zone to cast iron radiators that worked well in this house for the first 55 years. Use the oil boiler to heat the domestic water year round, so it's always warm ... oil is so ####ing expensive though :angry2:

Have seen the combination units .. one vessel, two sources of heat. what's the manufacturer of yours?

Trying to sort out an OWB for the next homestead that will tie into the existing 8 zone hydronic heating system through a heat exchanger, a bit more challenging for sure ... but way more space
w/ a domestic water coil in it!

 

[04titanse]

I just installed a wood fired boiler in my house last week. It heats all the hot water in my house, both the hot water for showers and sinks and also the hot water for the base board heat. I piped it in with my oil boiler so basically if the wood boiler is not producing enough heat my oil boiler with automatically come on. It produces more than enough hot water to make for steamy hot domestic water and also heat all three zones of hot water base board heat.

Basically you set the high and low temp cut off on the oil/gas boiler lower than the ones on the wood boiler so it doesn't come on unless the wood boiler drops below the low temp.

I post a few pictures of it tonight. The wiring needs conduit and a few little finishing touches, but it up and running.

 

[Encore]

I used to swear I'd never get an OWB. Love my wood stove and we achieved pretty comfortable warmth in the winter. Last winter was a little annoying because it was too warm to keep the stove running all the time so I was starting fires all the time.

We put in an OWB this summer(was offered one at a price I could not turn down) and thus far I absolutely love it. Perfectly even heat throughout the house, free hot water, exact temperature control and I can process wood in half the time it took me before.

If a person can get past the upfront cost, it's completely worth it.

 

[Martin Reece]

Are you referring to a wood-fired hot water heating system? Nope, don't know of any.

I am rather interested in hearing about how yours works, though. When I was young, I lived in a hot water heated house, and it was the most comfortable type of heat I have ever lived in. Wood fired seems like an easy addition to an oil fired system.

Someday, I hope to convert my house to a hot-water heating system, and I intend to add woodburning capacity.
Tell us more!

questions perhaps to answer:

You mentioned a "boiler", but surely you are just using hot water. Boilers are pretty dangerous, and generally only found in really old systems.

Do you have automated controls to limit the wood fired system exchange to the main system, or is it manually switched?

Do you have zone controls for each of the rooms, or is everything on a full circulation loop?

Does the hot-water heat use the same water system, or is there just a heat exchanger between the oil fired system?

It is a Benjamin Boiler. Made in Nova Scotia. It is all electronically controlled to limit water temperature and dampers for the wood side.We have 4 zone controls in a loop of copper pipe thru the house. It has two circulating pumps. One to move water thru the boiler once it reaches 120 degrees and another to circulate to rest of the house when the thermostat calls for heat. Also has a mixing valve to control cold water coming in for domestic hot water, which flows thru a series of coils in the boiler. I will try to post a couple of pictures tonite.
Martin

 

[Jim Timber]

Anyone ever added a waste oil injection system into their OWB?

Seems like the issues with WOB's is that they cake up and clog, and are hard to regulate to burn evenly, but if you simply added the oil into a wood fire you'd avoid that issue entirely.

I know waste veggie oil is getting harder to scrounge, and auto oil is being recycled for the most part these days - there's still the stuff you take out of your vehicles though.

 

[Big L]

It is a Benjamin Boiler. Made in Nova Scotia. It is all electronically controlled to limit water temperature and dampers for the wood side.We have 4 zone controls in a loop of copper pipe thru the house. It has two circulating pumps. One to move water thru the boiler once it reaches 120 degrees and another to circulate to rest of the house when the thermostat calls for heat. Also has a mixing valve to control cold water coming in for domestic hot water, which flows thru a series of coils in the boiler. I will try to post a couple of pictures tonite.
Martin

Hope you're hot water temps are higher than that! Fin tube radiation (aka: baseboard heat) or cast iron radiators, or a hot water coil in ductwork for that matter are designed usually for 180°f ...... duh, you're talking Celsius aren't you. Never mind :bang:

 

[Martin Reece]

Hope you're hot water temps are higher than that! Fin tube radiation (aka: baseboard heat) or cast iron radiators, or a hot water coil in ductwork for that matter are designed usually for 180°f ...... duh, you're talking Celsius aren't you. Never mind :bang:

Hi Larry,
The one circulating pump starts at 120 degrees F but that only circulates inside the boiler to prevent cold water getting onto the hot coils. It is set for 180 for the low and 200 degrees F for the high setting

 

[Martin Reece]

Martin, post a few pics of your Boiler when you have a chance..
Let us see what you are using..
Cheers..

Here are a couple pictures.

 

[Fifelaker]

Are you referring to a wood-fired hot water heating system? Nope, don't know of any.


You mentioned a "boiler", but surely you are just using hot water. Boilers are pretty dangerous, and generally only found in really old systems.

I don't know where you got the idea that boilers are dangerous or old. I can count 5 new residential boiler installs within a mile of my house. They are very common up here. also with the proper T&P valves and sensors, they are less dangerous than 90% of the wood stoves. The school I worked at had new Raypak boilers 1.8 million btu's for the two small schools and 2.7 (X2) million btu's for the hogh school installed 6-7 years ago. Not one saftey issue with any of them yet.

 

[pdqdl]

Anyone ever added a waste oil injection system into their OWB?

Seems like the issues with WOB's is that they cake up and clog, and are hard to regulate to burn evenly, but if you simply added the oil into a wood fire you'd avoid that issue entirely.

I know waste veggie oil is getting harder to scrounge, and auto oil is being recycled for the most part these days - there's still the stuff you take out of your vehicles though.

I have a waste oil burner in my shop. They work very well, but it would be a huge mistake to think you could add that type of burner to a wood fire. MOST waste oil burners work by pre-heating the oil a little bit, then mixing it with air and shooting it past an electric arc. That would be a disaster if the blast of air and oil were done in the same chamber as an actively burning wood fire.

I have heard of primitive waste oil burners that relied on dripping oil onto the wood fire to add heat, I imagine that would work with almost any wood burner. It would probably be pretty dirty burning, though.

*********************************************************

A terminology question for the well informed in this forum: My understanding has always been that a water heating contraption of any sort was not referred to as "a boiler" until it operates at temperatures above boiling. This means that the heating system is a true "steam heat" system, and that it is damned hot in addition to being under pressure.

Has it become common usage to call the hot water heating systems "boilers" ?

 

[pdqdl]

I don't know where you got the idea that boilers are dangerous or old. I can count 5 new residential boiler installs within a mile of my house. They are very common up here. also with the proper T&P valves and sensors, they are less dangerous than 90% of the wood stoves. The school I worked at had new Raypak boilers 1.8 million btu's for the two small schools and 2.7 (X2) million btu's for the hogh school installed 6-7 years ago. Not one saftey issue with any of them yet.

See, we are probably just talking about different terminology.

I come from a family of pipefitters, not woodburners. From my understanding, a boiler isn't a boiler unless it is boiling. Boilers are attached to steam heat systems, and everything is much different. The pipes are heavier, they require much more expensive system controls, circulators, and are pretty much never found in a house. Big industrial systems: you bet. Among other things, boilers are infamous for exploding when the pressure rises too high, so NO! A true boiler is not really safe unless professionally operated and maintained.

Home hot water system are great! I don't know why every home isn't built with them.

 

[Jim Timber]

Hot water heat involves additional care and expense to install when most people have the duct work installed for central air from the get-go. So it's a cost issue. Not having the extra dust is something most people don't understand, and they're super quiet too - that's nice when you don't hear your blower kick in as you're just falling asleep (big issue for me at our cabin).

Modern gas furnaces are also highly efficient. Our's at home now is something like 87% IIRC - it's only a few years old. I won't have natural gas in the new house, and will have to truck in propane - that convenience will diminish.

I'll have a conventional LP furnace with forced air (and AC), along with an outdoor wood burner, and I hope I can swing doing a geo-thermal grid as well but that looks like it might not be possible with my trees.

The idea behind burning waste oil, is just adding into the fire from cold. It doesn't smoke that much, and it's free. I wouldn't go to the trouble of pressurizing it, and a tube directing it into the burn pile wouldn't take much doing.

 

[blades]

Only problem with that is as heat radiates up the supply pipe the oil flow increases. Always has been a bit of a problem with simple drip feeds and used motor oil.

 

[Jim Timber]

But you could have it rigged to a solenoid to only flow when the blower was on or the vent was opened. I'm not worried about a consistent flow - it's more just a supplemental source of cheap/easy BTU's.

 

[Fifelaker]

See, we are probably just talking about different terminology.

I come from a family of pipefitters, not woodburners. From my understanding, a boiler isn't a boiler unless it is boiling. Boilers are attached to steam heat systems, and everything is much different. The pipes are heavier, they require much more expensive system controls, circulators, and are pretty much never found in a house. Big industrial systems: you bet. Among other things, boilers are infamous for exploding when the pressure rises too high, so NO! A true boiler is not really safe unless professionally operated and maintained.

Home hot water system are great! I don't know why every home isn't built with them.

The ones I speak of are pressureized systems so to my knowlege that would make them boilers as they will range from 160 to 250 degrees F depending on load.like I said I know of 5 new installs well within the last 4-5 years. Not cheap but efficient. Now what is called an OWB outdoor wood boiler is not a pressurized system so that is not a true boiler.

 

[bayard]

wood oil boiler

i have been using a northland wood oil boiler for 36 years. 5 t 7 cords a year .oil comes on if you forget to feed it. i use oil only for the shoulder seasons.lots of hot water, 72- 74 deg all day every day.k

 

[pdqdl]

The ones I speak of are pressureized systems so to my knowlege that would make them boilers as they will range from 160 to 250 degrees F depending on load.like I said I know of 5 new installs well within the last 4-5 years. Not cheap but efficient. Now what is called an OWB outdoor wood boiler is not a pressurized system so that is not a true boiler.

Thanks for the explanation. I was not aware that anyone was putting modern steam heat into houses.

From a thermodynamics perspective, steam heat is much more efficient than hot water heat. It also costs a great deal more to build, so the free wood burning outdoor "boilers" are going to probably be built hot-water only.