Wood-Oil Burner?

[Ian]

I recently purchased a large, drafty old home that's a good 3,000-square feet. It's an oil guzzler with a oil boiler that's a good 50-years old. My plan is to insulate as much as I can this summer, and hook up a wood stove in one of the fireplaces. I hope to nurse the old boiler along for another couple of years but I know I should prepare for the inevitable. I'm new to this stuff and wondered what the pros and cons were of going the wood-oil boiler route. I've looked a little into the Benjamin models, which seem to have some pluses.

But with these new machines do the issues around safety (two different heating units sharing the same flu) still exist? Is buying a boiler that does two different things really just mean I'm buying a unit that doesn't do either one all that well or efficiently?

If this is a good route for me, what models would you suggest for a house my size? What should I expect to pay? Any advice would be most appreciate.

Thanks,

Ian

 

[maple1]

I recently purchased a large, drafty old home that's a good 3,000-square feet. It's an oil guzzler with a oil boiler that's a good 50-years old. My plan is to insulate as much as I can this summer, and hook up a wood stove in one of the fireplaces. I hope to nurse the old boiler along for another couple of years but I know I should prepare for the inevitable. I'm new to this stuff and wondered what the pros and cons were of going the wood-oil boiler route. I've looked a little into the Benjamin models, which seem to have some pluses.

But with these new machines do the issues around safety (two different heating units sharing the same flu) still exist? Is buying a boiler that does two different things really just mean I'm buying a unit that doesn't do either one all that well or efficiently?

If this is a good route for me, what models would you suggest for a house my size? What should I expect to pay? Any advice would be most appreciate.

Thanks,

Ian

My input from 16 years of living with one: do not get a Benjamin, whatever you do. You can find previous input of mine in other threads on here with a quick search.

Mine outputs into one flue, but that may not be allowable in your area. I am determined this will be my last winter with this unit. I have spent a lot of time this winter researching exactly what to replace it with - bordering on obsession. The best solution efficiency wise (space permitting) is to go with 2 units - a gassifying wood unit (with storage), and a separate backup unit of whatever fits your situation best. I am waffling between a new oil unit & electric for that. If you wish to keep one unit with two fuel sources, likely either a Wood Gun or Tarm gassing unit with oil burner option - but there are options that have provisions for built in electric elements (Varmebaronnen & Empyre Elite for two) . There is a non-gassing wood/oil combo unit made locally here (Newmac) that I have yet to check price on - but I have a feeling that once I do it will be ruled out. I would like to support the local economy, but there's a limit to how much I would like doing that to cost me over the alternatives. There are likely other options I have looked at over the winter which are escaping me at the moment.

 

[mark123]

I had a CC500 Benjamin as well, I would not get one of those, it has a pretty low BTU output on the wood side ( I think 70,000-80,000), it was designed to run on both wood and oil not one or the other, I always had the oil burner shut off and it would not keep up to my heating demands. I sold it and bought a Woodgun with built in oil burner and it only has 1 flue output. A lot more money but It has no problem keeping the house toasty on wood only.

 

[Mainewood]

I had a CC500 Benjamin as well, I would not get one of those, it has a pretty low BTU output on the wood side ( I think 70,000-80,000), it was designed to run on both wood and oil not one or the other, I always had the oil burner shut off and it would not keep up to my heating demands. I sold it and bought a Woodgun with built in oil burner and it only has 1 flue output. A lot more money but It has no problem keeping the house toasty on wood only.

For the record, I have been selling & installing Benjamin heating products in northern New England since 2005. I spent some time reading the posts here about the Benjamin CC-500 and can appreciate your frustration. If you were not properly instructed on the firing procedure of the boiler than you will quite naturally experience some of the problems you have had. My purpose is not to change your opinion of the Benjamin boiler, but to offer some operational tips that I hope will be helpful to anyone using a Benjamin.

1. The CC-500 is a wood/oil combination boiler and is not designed to run on wood only. Many have turned down the oil aquastat settings to prevent the oil from firing. I have found the optimum temp for fhw heat is around 180. Normal operation would allow the oil to fire whenever the wood temp drops below say 150. The oil would fire until it returns the temp to say 170. The idea is to heat primarily with wood and use the oil to maintain temps when the wood comes to the end of it's burn cycle. Keep in mind that the coal bed from the fire is still supplying heat into the common water vessel even after the fire has burned down.
I have been heating my 2700sf. Colonial with the Benjamin CC-500 for the past 5 years. My average annual consumption of wood is 5-6 cords and 200 gal. of heating oil.

2. Another common problem observed is excessive creosote. Creosote forms when the temp. in the wood combustion chamber, breech pipe or chimney is too low for extended periods of time. A "butterfly" damper should not be used in the breech pipe. The automatic damper on the loading door will provide the best firing to avoid creosote. Gasification wood boilers burn at much higher temps, thereby avoiding excessive creosote. I have found that I can use my boiler successfully if I burn wood continuously only when daytime temps are below 40 and or there is sufficient demand for heat in the house to cause the automatic damper to cycle open regularly so temps get high enough to avoid creosote. Alternatively, small (hot) fires can be made in the morning or eve. in warmer temps.

 

[maple1]

The CC500 may be adequate for some situations, e.g. quite low heat loads, or if one is happy with their oil burner operating that much despite loading enough wood btu's into the unit that oil should not be needed at all. Your figures are close to mine - I use a couple more cords of wood and about the same oil. After our long time together, I know quite well how it reacts to different procedures - lowering creosote production via allowing even more heat to go up the chimney & not be recovered is not very efficient operation. If one is content operating in this way, and happy tending to it multiple times per day during heating season, I wish them well.

EDIT: Another wood/oil choice that looks promising is the Biomass combo unit.

 

[TimCroft]

I recently purchased a large, drafty old home that's a good 3,000-square feet. It's an oil guzzler with a oil boiler that's a good 50-years old. My plan is to insulate as much as I can this summer, and hook up a wood stove in one of the fireplaces. I hope to nurse the old boiler along for another couple of years but I know I should prepare for the inevitable. I'm new to this stuff and wondered what the pros and cons were of going the wood-oil boiler route. I've looked a little into the Benjamin models, which seem to have some pluses.

But with these new machines do the issues around safety (two different heating units sharing the same flu) still exist? Is buying a boiler that does two different things really just mean I'm buying a unit that doesn't do either one all that well or efficiently?

If this is a good route for me, what models would you suggest for a house my size? What should I expect to pay? Any advice would be most appreciate.

Thanks,

Ian

Ian,

I installed a Tarm excel boiler 6 years ago. It is a wood oil combo with separate combustion chambers and heat exchangers. It attaches to chimney in 1 flue. I bought it because I couldn't conceive of not using some oil. I installed an STSS storage tank at Tarms recommendation. The storage tank give the Tarm the ability to burn flat out and dump any unused BTUs into storage which also heats DHW. I have not burned a drop of oil in 6 years. Have since installed Solar hot water also ( another story). The Tarm and STSS were well over ten grand together and I did the install. . My oil consumption was 1200 gallons per year and I swallowed hard on the idea of a 10 + year payback. Now oil has doubled and it ain't goin down! With a 2200 square foot old house, the Tarm and tank have paid for themself this year all in. The Tarm is about 83-85% efficient on oil with a Beckett gunt and the downdraft gassifier for wood leaves NO creosote in the chimney, just ash.

Would recommend the TARM. It is a finely crafted machine.


Tim

 

[muncybob]

Along with mark123 I also have the WG wood/oil combo into 1 flu. The Tarm does indeed appear to be a fine unit but we didn't have the room to put in storage for it.
I rarely use oil so the alleged lower efficiency of the oil side does not bother me at all. I say alleged since we use so little oil I really have no idea how efficient it is but many have said the oil add on burners are not very efficient. We had an old oil boiler on it's last legs or I would have gone the seperates route.
Into 1 flu is not a concern as the WG will only run 1 fuel at a time...properly set up, there is no way for the oil and wood to run at the same time. If the oil does kick in due to lack of a wood fire you must manually reset the unit to once again burn wood which is probably a good idea. Of course you should check with your locality and insurance company about 2 appliances into 1 flu.
Based on the oil we consumed before going to wood our payback period was about 3+ years which come to think of it, is right about now!

 

[maple1]

After reading on here how little oil some are using after getting their new wood unit on line, and after spending all winter pondering my own situation, I think I have come to the conclusion that an oil unit of any kind (combo or separate units) is not the way to go - I am getting rid of all my oil stuff & replacing with a way-cheaper electric boiler for heat back up, and regular electric DWH tank with sidearm heat exchanger & DWH coil in one of my storage tanks. The only time any backup (electricity) will get used is if we are away for a couple of days in the winter (a rare occurance), or if I get lazy with lighting a fire every week or so when it's not heating season - even then it won't come close to the $1k/year we pay now (would be more in the future with the way oil prices are going) for oil. Getting rid of the oil tank will be a big plus, and not worrying about fuel & burner sitting around unused for long periods of time & wondering if it'll fire when I need it is also a plus. I would also need to buy a new oil unit if staying with oil, which was also a factor - along with our tank nearing 20 years old.

 

[G10mm]

I have just put in a Newmac wood/oil/coal boiler in the house . And I all ready saved a lot of oil. I got the Newmac do to township regalations. If I put a wood Gasification boiler out side I would have to go throw the same regs as if i was biulding a house . And if I got an other boiler in the house I would have to install a all fuel Stainless steal flow pipe The newmac boiler has one flew so all I had to do was get rid of my old boiler and put that one in and hook it up and go .And the newmac can use oil as a back up or primary or not at all. Used to burn 5 to 6 tanks of oil a year (330 gal/ 1089 liters if my convertion is right). If you get the grates pakage you can use coal as well ( havent used that yet) I would have liked to get a Gasification boiler but I looked a round and didn't find that combo (I know ther out there ) With the oil back up If I need to go out of town for something for a coply of days .All I have to do is throw a switch and I have oil heat so I don't have to worry about the house getting cold .Or getting some to feed the the fire . I would recamend newmac If you have one chimney to use and putting anything out side would be a problem