Question for everyone burning in a wood forced air furnace...

[CowboyAndy]

What is your overnight burn procedure? It just seems that I am not getting what I should out of an overnight burn...

1 - 1 1/2 hours before bed I get the house nice and warm, usually up to 75 or so by using a few smaller splits of a soft wood (currently boxelder). Then, I start with a few pieces and let them get going pretty good. Then I continuosly load the rest of the wood until the firebox is full. I give that a few min to warm up, then reduce the air to minimum (its a newmac furnace and has the draft inducer fan with a control next to it that restricts how much the fan can blow). Then I go upstairs and turn the tstat down to 69 (which just turns the draft fan off until the temp drops a bit).

My success with a solid overnight burn is not that great. Most mornings wake up and the house is 63 (thats when the oil is set to come on) and the oil burner is usually running. There is a bed of coals, but they are minimal.

At night, I burn exclusivly sugar maple.


What does everyone else do?

 

[CowboyAndy]

Dont have a flue damper, the installation manual for the furnace said thats a big no no because its a combo unit...

 

[smokinj]

Dont have a flue damper, the installation manual for the furnace said thats a big no no because its a combo unit...

barometric damper on it?

 

[Badfish740]

I have a whole bunch of locust I just scored that I'm going to save for overnights. We'll see how it goes.

 

[Eric Johnson]

I always had dampers on my conventional furnaces and boilers, including combination units. I'd install a cast iron damper like Pook says ($5 at a hardware store) and try it for awhile to see how it works. Just shut off the oil side while you're experimenting with it. You might well find that you really don't need the oil backup once you figure it out. There are obvious safety concerns with having a damper on an oil-burning appliance, but really all that does is compromise your ability to burn wood efficiently. You've got a lot of your heat going right up the stack when your burn a conventional wood-fired furnace without as stack damper, IMO.

With dry hard maple, your house should be nice and warm in the morning and you should have a nice bed of coals going.

 

[smokinj]

Dont have a flue damper, the installation manual for the furnace said thats a big no no because its a combo unit...

barometric damper on it?

oil/wood combo must have barometric, i think

i dont think he has one on there? not sure ?

 

[Eric Johnson]

That's assuming they insure combos at all, which if they had any sense, they wouldn't. But that's a valid point.

I don't think it's safe to vent an oil burner and a wood burner into the same flue to begin with. What I'm getting at with my post above is for CowboyAndy to try to figure out how to heat his house with the wood side exclusively, and then just use the oil side for vacations and maybe during the shoulder seasons. The danger with using the same flue for both is that the chimney could become clogged with creosote, resulting in potentially tragic consequences if the oil side switched on.

In my opinion, the only safe way to operate a combo is to disable the oil side when burning wood, then thoroughly clean the chimney before switching back to oil.

 

[smokinj]

That's assuming they insure combos at all, which if they had any sense, they wouldn't. But that's a valid point.

I don't think it's safe to vent an oil burner and a wood burner into the same flue to begin with. What I'm getting at with my post above is for CowboyAndy to try to figure out how to heat his house with the wood side exclusively, and then just use the oil side for vacations and maybe during the shoulder seasons. The danger with using the same flue for both is that the chimney could become clogged with creosote, resulting in potentially tragic consequences if the oil side switched on.

In my opinion, the only safe way to operate a combo is to disable the oil side when burning wood, then thoroughly clean the chimney before switching back to oil.

I would say you are right my furance is set up as a stand alone.

 

[johnsopi]

I did not think that it was allowed to use the same chimney for two burners. I have a chimney for my wood furnace and a power vent for the
oil furance. I don't see in Andy's post that he is saying that he's using a shared chimney.
But back to overnight burns. If it's cold out I have to reload my Yukon Big jack during the night. I have a barometric damper would replacing it with a inline damper get longer burns and would this be at the risk of more creosote build-up?

 

[Eric Johnson]

Combination units are allowed to use the same flue. Most do. It's a big loophole in the code. If Andy's used separate flues, then putting a damper on the wood side wouldn't be an issue.

I've never used a barometric damper, but they're not usually used with wood-fired appliances. I can think of a couple of reasons why not, including the fact that they're harder to seal up in the event of a chimney fire.

The beauty of a manual cast-iron damper is that you can adjust it to compensate for changes in the draft. On a very cold night, for example, you'd have the damper mostly closed, and in the process, keep much of your heat from going up the chimney. In warmer weather, you open it back up. Of course, you need to keep an eye on it.

I don't think a damper will reduce creosote formation. Probably just the opposite, since a cooler flue would tends to promote creosote formation. It's kind of like comparing a Franklin Stove with an airtight stove--the tradeoff for increased efficiency between those two technologies is the potential for creosote.

 

[MrEd]

Slightly OT:

Has anyone ever actually seen *first hand* that an insurance company bailed on paying a claim by faulting the homeowner for something? I know its often thrown out there as something to worry about, and of course you should do things "by the book", but sometimes I wonder if we worry about "what the insurance company might say" a bit much....

For example, when I bought my house I got insurance, no inspection was done on anything by the ins. co. How would they ever be able to prove that *I* did something wrong, versus a previous owner? What if some wiring was done wrong(say w/out permit) before I moved in? Could they even legally deny a claim? If this was the case I say any house over a certain age likely has many, many reason to deny claims....but I never actually hear of this happening??

 

[Badfish740]

Slightly OT:

Has anyone ever actually seen *first hand* that an insurance company bailed on paying a claim by faulting the homeowner for something? I know its often thrown out there as something to worry about, and of course you should do things "by the book", but sometimes I wonder if we worry about "what the insurance company might say" a bit much....

For example, when I bought my house I got insurance, no inspection was done on anything by the ins. co. How would they ever be able to prove that *I* did something wrong, versus a previous owner? What if some wiring was done wrong(say w/out permit) before I moved in? Could they even legally deny a claim? If this was the case I say any house over a certain age likely has many, many reason to deny claims....but I never actually hear of this happening??

I think the basic idea is that the point of the insurance industry is to collect as many premiums as possible and pay as little benefits as possible. You do raise a legitimate point about how many things are done to homes over the years. My insurance company did no inspections and when I called to ask about the stove they simply told me that as long as a permit is pulled and the inspector signs off on the install it's ok with them. In any event it's wise to err on the side of caution because for most folks, if they lost their home to a fire and the claim was denied it would be the end for them. It would be for me anyway.

 

[Eric Johnson]

I think it's overrated and probably regulated to some extent in most states. Insurance coverage is a competitive business, and if a company gets a reputation for denying claims based on technicalities, they're not going to sell many policies. It's not like your car insurance company says: "you were at fault, therefore we're not going to cover your claim." Doesn't happen that way. They cover the claim and then raise your premiums.

They don't cover fraud, obviously. But they do cover stupid.

 

[MrEd]

Thats what I was thinking, if I get drunk and smash up someones property (or worse kill someone) with my car, the insurance doesn't get a pass on paying the claim - and clearly driving drunk is illegal.

If anyone has a real link to an actual news story about some homeowner that's claim was denied on a technicality (i.e. no permit), I'd like to read it (I am not doubting that they exist, I really would like to read it).

My own policy has something to the effect of "substandard work" being a reason to deny a claim. I've seen plenty of permitted/inspected projects that are substandard...permitting really has not much relation to quality, imo.

 

[Eric Johnson]

Which is a pretty broad definition, giving the Ins. Co. plenty of latitude. My point is that from a marketing and business perspective, it's not in their interest to go around denying claims just because they can.

 

[CowboyAndy]

Okay, to answer some questions:

yes, it is a shared flue (8"). The furnace is UL Listed for use in a shared flue.

Yes, there is a barometric damper

I can disable the oil by switching off the tstat. it is only on from 10p-5a as a backup, the rest of the day the tstat is off completly.

An insurance company can't deny your claim, even due to neglegance...that's why you have insurance! But, as soon as they pay the claim they will drop you like a bad habit and your next company will charge you 5x as much...

IMO an oil furnace hooked to a flue that could become blocked by creosote is just as dangerous as a wood burning stove hooked to a blocked flue...



So, if I install a damper, at what point do I close it? How much?

 

[Eric Johnson]

Probably more dangerous because (just guessing) there's more CO in oil exhaust than in wood exhaust. Even if there isn't, you notice it more quickly.

The way you set a manual damper is by closing it until the smoke starts to back up into the room, then open it up slightly. Since the damper itself has holes in it, you can't block off the draft completely, even if you close it all the way. The way I used to do it was to open it up completely when loading/starting the stove, then damp it down 1/4 or 1/2 of the way once things got going. You figure it out pretty quick. Plus, if you ever do have a chimney fire, it's nice to have the damper to help keep things somewhat under control. Or at least it provides you with the illusion that you have some control.

A damper is a really useful device. You can tell how much soot/creosote is building up in your stove pipe simply by turning the damper to an extreme position, for example. As noted, it gives you a lot more direct control over your fire, too. And, as I said, they cost about $5 and take around 15 minutes to install. If you don't like it, just leave it open and it won't interfere with the rest of the system.

 

[mike1234]

I don't think you want to install a damper, just too dangerous, what if the oil furnace kicks on? CO2 in the house, worst case, you are all dead.
You have a damper, it is a barometric damper. Make sure it is set right. Only someone with the proper tools can do that, usually an HVAC person. If you set it yourself, you'll either run the stove pipe too cold, and have to clean it a lot (that is what I tend to do) or too hot and loose lots of heat up the stove pipe.

If you set it yourself, make sure it is set up for the correct run, horizontal or vertical pipe (it's listed where the weight on the damper is) and then make it so it tilts out on it's own. Clean the stove pipe monthly.

I have started to get about 7 hour burns doing basically what you are doing.
1. Get the house up to 74 or so, lots of hot coals.
2. Load it up and get it roaring at bedtime.
3. Shut down the air, way down, but depends how cold it is out
4. Turn the thermostat down to 70.
5. Go to bed at 10
6 Get up at 5, lots of hot coals, house it 70ish.

If it's not too cold out, I can burn whatever, if it is COLD, I put in the good stuff, Hedge or Oak.
I also have been cleaning the stovepipe monthly, and December it was bad, too much idling, January 1/2 as bad, so I am getting better at it.

 

[Eric Johnson]

As I said, I'd disconnect the oil side before installing and experimenting with the damper.

 

[laynes69]

Andy is your furnace operating on a forced draft? I know you can shave a few hours off a burn if your forced draft is operating constantly. I also agree with the baro. I have one, and my furnace is strictly wood. I could tell a huge difference with it operating. I check my flue often, and keep an eye on the chimney to help keep things going good. That baro should slow that draft, and allow for more heat to be held in the unit. I have both on my flue, and the manual always stays open, while the baro works. I don't know how much more of a burn you can get with a manual damper, only because you currently operate with a baro.

 

[pybyr]

Which is a pretty broad definition, giving the Ins. Co. plenty of latitude. My point is that from a marketing and business perspective, it's not in their interest to go around denying claims just because they can.

Insurance varies A LOT by the company, and even the adjuster/ investigator handling the claim- actually, even the point in history (when the insurance companies' portfolios are taking a hit, they are likely to be more cautious in paying claims).

The extent to which a State polices insurer conduct also varies widely by State/ region.

Don't assume the market is self policing-or that the gov't is doing a competent job regulating haven't we noticed that lately in other financial services ?

Most of all, it's a good idea to follow safety standards as best you can, as getting paid is sorta secondary to remaining alive, in good health, and avoiding the disruption of a house fire.

Back to the topic of overnight burns in warm air wood furnaces, I never had much luck getting my prior otherwise excellent unit to do a burn that long. If I loaded up the firebox and damped it down with either the inlet air or a stack manual damper, then I got a really grubby burn which gave me all sorts of signs that it would not be long before I'd be building up tons of creosote (when you hear a crunch as you rotate the manual damper, you know you just did a burn that left a lot of combustible stuff inside the pipe). In the end, I settled for faster hotter fires that got the house as warm as I could before I went to bed, and grit my teeth that the oil would come back on by morning. This is one of the main reasons that I sold my otherwise well-working wood air furnace and am going to the trouble of putting in the gasification boiler.


Good luck

 

[smokinj]

Andy is your furnace operating on a forced draft? I know you can shave a few hours off a burn if your forced draft is operating constantly. I also agree with the baro. I have one, and my furnace is strictly wood. I could tell a huge difference with it operating. I check my flue often, and keep an eye on the chimney to help keep things going good. That baro should slow that draft, and allow for more heat to be held in the unit. I have both on my flue, and the manual always sta.ys open, while the baro works. I don't know how much more of a burn you can get with a manual damper, only because you currently operate with a baro.

I tryed it last night winds where low under 10mph so i put a cap on the baro so it woulnt leak smoke choke the manual damper all the way had good heat all night and 8 in. coal bed this a.m. and still blowing good heat , So will it work in high winds NOPE. Thats why i put the baro on in the frist place, so with the cap in place its easy enough to change back to the baro in hi winds! (I already use the baro T for clean out)if i choke it all the way with the baro in place there is alot of smoke spillage

 

[ikessky]

My proceedure is roughly the same as what mike1234 posted earlier. I usually get about 6-7 hours once I pack the stove full. I could probably get more, but I would rather burn a little hotter and not risk loading up with creosote. I mainly burn hard maple and white ash. For my overnights, I usually try to use larger splits and some rounds.

 

[smokinj]

My proceedure is roughly the same as what mike1234 posted earlier. I usually get about 6-7 hours once I pack the stove full. I could probably get more, but I would rather burn a little hotter and not risk loading up with creosote. I mainly burn hard maple and white ash. For my overnights, I usually try to use larger splits and some rounds.

I have been running that way not had to clean the pipe at all this year clean clean clean but iam going through the wood very fast.Not a huge problem because i have alot of it but working harder not smarter not always a good thing.Eric pretty darn good at this and what i seen last night enough to make me think a couple of changes are in order. Now cowboys a different story he has oil back up! Running season oak and hege changes thing as well.I ran hedge last night choke down at 10 pm still blowing at 7 am.(thank for the tip Eric) Ill open it up an hour in the a.m. and maybe a couple at night weather dictating this.The Best I have seen doing it the other way blower shutting down about 4 am and 1in. or 2 of coals easy enough to get going but far from blower running good at 7am and it was 16 degree here last night