Wood burning furnaces

[tvanvranken]

The best way to learn is by doing. Installed a wood burning furnace this past fall at my home and after 3-1/2 months it is totally creasote covered to the point that the draft inducer won't open. Research and conversations with my preferred chimney sweep, let us to conclude that the fire was not burning hot enough! What a lesson learned the hard way. Now I have to replace all the exposed flue in the basement and start on the lined chimney! My questions is this, would it help to introduce fresh air into the cold air return? My main heat source is a high efficiency heat pump by Bryant. Any ideas on getting the furnace to burn hotter would be greatly appreciated.

[Joe Funderburk, CMI]

I have a Taylor wood boiler that sits out in the yard. I don't have the types of issues you have. Suggest you speak with the manufacturer.

Getting wood to burn hotter is a simple matter of throwing more oxygen to it. Of course, that means you'll also burn up your fuel faster.

[Larry D. Kage]

Originally Posted by jfunderburk

I have a Taylor wood boiler that sits out in the yard. I don't have the types of issues you have.

I have an air tight fireplace insert and don't have those creosote problems, either. I sized my unit for proper burning and comfort.

Originally Posted by jfunderburk

Getting wood to burn hotter is a simple matter of throwing more oxygen to it. Of course, that means you'll also burn up your fuel faster.

And, it'll bring the inside temperature way up.

Did you size your wood burning furnace for your space to be heated?

Do you use seasoned wood?

[Brian A. MacNeish]

Originally Posted by lkage

I have an air tight fireplace insert and don't have those creosote problems, either. I sized my unit for proper burning and comfort.

Did you size your wood burning furnace for your space to be heated?

Do you use seasoned wood?

Most wood burning furnaces are way too big except for the coldest weather.......at other times, they smoulder at low temps that lead to creosote from incomplete combustion and too low flue gas temps.

Wood should be seasoned up off the ground in rows with air spaces between and covered to prevent wetting from rain. Six months drying at least is recommended.

[Brian A. MacNeish]

Here's a good booklet on residential wood heating. In the past, I have been one of the reviewers of this document before going to print.

http://www.cmhc-schl.gc.ca/en/co/mah...ating_EN_W.pdf

[rbero]

I have an englander add on furnace i burn about 4 full cords a year i clean my chimney 1 time a year and i have to clean my 6 inch black pipes about once a month, the wood im using is oak cut from standing dead trees and was all cut and split by june. If you would add intake air it will make it burn hotter because cold air has more oxygen than warm air and if your home is pretty air tight it would help alot remember when mom uses the dryer it vents outside and sucks air from the house thus taking air from the wood burner same as the fart fan and the furnace if it draws from inside the home

[Marcel Gratton]

Most wood furnace are too big for the average home which results in a smouldering fire and creoste build-up.

Only fire up the furnace when the temperature is very cold using dry hard wood. Smaller hotter load should help keeping the pipes / flue cleaner.

[tvanvranken]

My wood furnace has an air intake on the ash door and one on the on the wood supply door. Both are wide open. I have been using year old hard woods since I started up the furnace in October. I was thinking of running a pvc air intake to bring in fresh air from the outside to the cold air return. Unfortunately the intake will have to be about 15' long.

[David A. Andersen]

The furnace should not smoke!

It smokes because of two things; bad wood and insufficient combustion air.

Insufficient combustion air may be the result of two things; there is no combustion air available or the furnace damper is closed down to control heat output (the oversized unit for the size of the house people are talking about).

Just like any HVAC unit, "bigger is better" equipment does nothing but drive you crazy!
If the inside of the furnace is not hot enough, the creosote actually "condenses" in the furnace and flue.
This unit is for "supplemental heat" and should be undersized (or sized below the average daily temperature during the winter months for your area).

One last thing, inadequate system design will prevent inefficient operation at low temperature output settings.
My wood furnace is so efficient that on the low setting, the flame of the fire burns in the air above the wood, not at the wood (in essence I am "burning the smoke")! You can not tell if the furnace is running from the exterior unless you can see the heat waves above the flue! My unit has a very complex air injection system at several locations within the firebox. Adding combustion air at the top of the firebox causes smoke to burn when it is above above its flashpoint. The top of the firebox generally does not have sufficient oxygen left to burn smoke and the combustion byproducts which cause creosote.

In 5yrs of heating my house with this unit, I have not "HAD" to clean my furnace! I clean it, but there's nothing to clean!

Your furnace may just be a piece of crap!

[tvanvranken]

Thanks to all. I am beginning to see where I can make improvements to my system. It is all about the burn!

[rbero]

what kind of furnace do you have any pics of the set up?

[greg]

Originally Posted by jfunderburk

I have a Taylor wood boiler that sits out in the yard. I don't have the types of issues you have. Suggest you speak with the manufacturer.

Getting wood to burn hotter is a simple matter of throwing more oxygen to it. Of course, that means you'll also burn up your fuel faster.

How do you like the wood boiler? I just purchased a used (2 year old) Central Boiler. I haven't hooked it up yet, but will be digging and pouring the pad this week, after I shovel the snow out of the way. I have a heat pump and am looking forward to warmer air and lower electric bills.
Any tips or suggestions for hooking them up. There seems to be a multitude of ways to wire and plumb them.