Question about wood furnace safety in event of a power outage

[cwatkin]

I currently own a Hotblast model 1400 wood furnace made by the U.S. Stove Company. Before moving to my new location, I only had a wood stove which didn't matter if the blower was running or not.

The plate on the outside of this furnace states that the lower damper should be left open to mo more than one turn and wood not loaded more than about half full in the event of a power outage where the blowers aren't running.

I have the unit connected to a battery backup such as would be used for computers. I looked up the specs on the furnace and the two blowers draw a total of 600 watts (300 watts each). I also looked up the specs on the backup unit I have and it will run for 7.5 minutes at the full 600 watts and 20 minutes at 300 watts. As connect at this point in time, it will draw 600 watts.

If home, this will give me enough time to get it going on a generator but my main concern is what would happen if I wasn't home and the condition were set for a full power burn? I am picturing the Fukushima reactors in Japan melting down once outside power for cooling was cut. Is this a major fire hazard or would it just lead to damage of the furnace? How should I handle this?

I have thought about wiring the blowers so that one would run, drawing only 300 watts if the power goes out to give it a longer runtime. Is that a bad idea or not? Anyone have better ideas? Should I invest in a larger battery setup? I have also thought about trying to rig something up that would close the main damper all the way if power is lost for more than a minute or so.

Thank you,

Conor

 

[iowa]

Where are you at in the Ozarks?

 

[NCHornet]

I have only had my Hot Blast 1557M installed for a couple weeks now but I have done a lot of research on this subject. I found countless people who never even plug their blowers in. They simply rely on hot air rising to heat there home. I tried this and it did ok, but the heat was very uneven. My question for you is why would you build a full power fire if you aren't going to be home? If you are worried about it I would opt for one fan running longer than 2 fans running for 1/2 the time. If I were you I would just put a small load in the box while you are gone and worse case scenario is you have to start a new fire when you get home. I have ran mine both ways and I can say for my needs the stove heats the house much better with the blowers running.
NCH

 

[cwatkin]

Where are you at in the Ozarks?

I am about 10 miles south of Rolla, MO near the small town of Vida if anyone knows where that wide spot in the road is located.

Conor

 

[cwatkin]

I have only had my Hot Blast 1557M installed for a couple weeks now but I have done a lot of research on this subject. I found countless people who never even plug their blowers in. They simply rely on hot air rising to heat there home. I tried this and it did ok, but the heat was very uneven. My question for you is why would you build a full power fire if you aren't going to be home? If you are worried about it I would opt for one fan running longer than 2 fans running for 1/2 the time. If I were you I would just put a small load in the box while you are gone and worse case scenario is you have to start a new fire when you get home. I have ran mine both ways and I can say for my needs the stove heats the house much better with the blowers running.
NCH

That is good to know. I usually try not to have a huge fire going and put the dampers in just to keep more even heat so it isn't freezing when I get home but just wondered for "worst case" planning. There is no comparison in the heat output if the blowers are off so I would never opt for this option. Anyway, I may wire up one blower to run just to be safe. I may setup something to e-mail me if the power goes out while I am at work just so I know.

Thanks,

Conor

 

[Dalmatian90]

I may setup something to e-mail me if the power goes out while I am at work just so I know.

Don't know your home setup, but make sure your internet doesn't normally go down too! Even if your modems and such have battery backup, doesn't mean the network will stay up. Cable you're probably screwed, DSL or Wireless 3G/4G you'll have time to get notification out.

Cable will go out immediately with neighborhood wide blackouts, their repeaters don't have battery backups.

If you're wired direct to a telephone Central Office then DSL will stay up indefinitely, but there's a 18,000' cable distance limit so beyond 3 miles or so, and maybe less in dense areas, you'll go through a Remote Concentrator that takes neighborhood copper lines and repeats them over fiberoptic to the local CO. My experience with those is they'll die in 12 hours. The RCs here are wired to be run by generator...but you have to wait for AT&T to tow the generators out to them, and that took four or five days back in August...I'm thinking those gensets might be national assets that AT&T doesn't even keep in state but just trucks from a central depot to the natural disaster of the month.

Wireless around here except for Verizon you get about 8 hours and their batteries die. Verizon Wireless must have generators or fuel cells at their cell sites in my town, it was the *only* telecom with continuous service after Irene in August.

Connecticut's been slowly working on a statewide fiberoptic network to connect all the town halls / 911 centers / state facilities / hospitals / police stations / fire stations / schools / radio towers together. Big $$$$$$. I was a bit leery of it before, but after Irene I know understand just how much our telecommunications infrastructure has degraded over the last 30 years -- you just can't rely on the telephone network to stay operational after major events anymore. Fiberoptic doesn't need relays, as long as you have power (from generators) at either end the gear will work.

 

[cwatkin]

You think like I do. Considering my work relates to natural disaster prepardness, this is definitely something to think about. Besides being cheaper, wood gives you reliable energy in the event of an energy crisis or shortage and there is no shortage of wood on my property.

I am on DSL in a rural area. It is my understanding that I am about at the end of the line but I am guessing I will have some time for backup to hold out. All of my network/computer equipment is on backup with a beefy surge protector plugged in between the backup and the wall. We seem to get random voltage fluctuations around here no matter the weather conditions and I work with computers and know that this is killer on such sensitive electronic equipment. A complete power loss is easier on this stuff than a brownout where the lights flicker. Also, I am not sure but think that the DSL/phone lines around here might be buried while the power is all overhead lines. This should make that more reliable in an event such as wind that takes down overhead lines.

Either way, it sounds like I could probably count on this setup for a notification if power is lost. To make it even better, I could hookup an old cheapo laptop with a decent battery that I have to make that part run even longer. I already have this for several weather notifications so why not use it for other things too? I would probably have my alarm set to notify me starting after a 30 second outage to avoid false alarms from the all too frequent momentary outages around here. I would have repeat confirmations of an outage set at one minute intervals after that period of time. I guess if I wanted to get super reliable, I could have some type of notification sent if my computer at home loses commincation with the outside world. I could judge this how I want, depending on the weather. If it is nasty out, I can guess the power is also down.

I have generators and plenty of fuel. One is a nice 8000 running watt/13500 watt peak unit that can run my well pump and everything else here (have to pick and choose) but the electric heat, which I try not to use anyway. I also have a 1200 running watt/2000 peak watt cheapo that I picked up at Aldi (yes, the discount grocery store) for very cheap that would run the fridge and wood furnace blowers no problem. This is much smaller and burns MUCH less fuel so I would only run the large one to pump water and MAYBE cook on the electric range if the outage was prolonged. The cheap Aldi generator is Chinese but seems to be well made and works well. It has features not seen on a lot of U.S. made generators of this size such as a cast iron cylinder bore and such. I have been told that the engine is a Honda copy and it includes overhead valves and all. For a 4-cycle, the unit is light and easy to carry without wheels. For the price, you could buy two and keep one as a spare and still be money ahead when compared to the cost of most generators. I don't think I paid much over $100 for this. I saw it in the store and came home and looked at the reviews, which were all positive. I got one the next day and they were gone the day after that. This unit is quiet unlike my big monster that is painful to be near. I am sure it would meet the sound requirements at many campgrounds.

Conor

 

[Dalmatian90]

Also, I am not sure but think that the DSL/phone lines around here might be buried while the power is all overhead lines. This should make that more reliable in an event such as wind that takes down overhead lines.

There's a few roads around me like that. Not common, but not exactly very rare either. Seems to be a late 60s / mid 70s thing they did. Phone lines are easier to bury then power lines (you don't have to worry about electrocuting someone, and you don't have to worry about dissipating heat from power lines).

Overhead phone lines very, very, very, very seldom break. Several factors combine for that.

The first is there's so many wires -- the "typical" yeoman telephone cable has 600 pairs -- 1200 wires divided internally into 24 bundles each with 25 pairs of color coded wires. It's just damn strong. Even smaller cables serving further out reaches will usually have a few hundred wires; the minimum is 50 wires (25 pairs) unless it's something really unusual deep in the boondocks.

Power lines have far fewer conductors, I believe the wire doesn't stretch as well, and typically on cross arms which add another energy-absorbing weak spot. So a tree falling first hits the power lines which absorb a lot of the impact until they break, and there just isn't as much force left to hit the stronger the telephone lines.

I've seen hundreds of broken power lines over the years, and I've seen a handful of cable lines snapped. I don't think I've ever personally seen a single telephone line (other then one going to an individual house) broken. Been stripped off the pole and just need to be put back up, yep. But actually not working broken, nope. I know it happens because I've heard of it and seen pictures, it's just very rare.

Power guys can measure the time it takes them to repair a broken line in tens of minutes usually, maybe a few hours for a complex situation. Telephone folks when a cable does snap start talking in tens of hours and how many days it will take to splice all the wires back together and test them.

Fiberoptic doesn't have the strength of bundled wires that copper phone cables have, but like them they're protected by the wires above them breaking the fall (including copper phone cables), and there's design incentives to have the mounting hardware break away and let them simply strip off the pole instead of snapping...so that you only need linemen to tack them back up and you don't have to call out a specialized splicing truck and crew to actually repair the line itself.

 

[JeffHK454]

Heat dump....

 

[jeeptj19992001]

install a generator problem solved.

 

[BSD]

That is good to know. I usually try not to have a huge fire going and put the dampers in just to keep more even heat so it isn't freezing when I get home but just wondered for "worst case" planning. There is no comparison in the heat output if the blowers are off so I would never opt for this option. Anyway, I may wire up one blower to run just to be safe. I may setup something to e-mail me if the power goes out while I am at work just so I know.

Thanks,

Conor

My father has a patented battery backup system for heat systems. totally seamless power management in the event of a power failure he gets about 3 days run time for his boiler ("normal" use, where it cycles on and off). you could very easily put it to use on an OWB or indoor unit. if you want details PM me.

 

[zogger]

I currently own a Hotblast model 1400 wood furnace made by the U.S. Stove Company. Before moving to my new location, I only had a wood stove which didn't matter if the blower was running or not.

The plate on the outside of this furnace states that the lower damper should be left open to mo more than one turn and wood not loaded more than about half full in the event of a power outage where the blowers aren't running.

I have the unit connected to a battery backup such as would be used for computers. I looked up the specs on the furnace and the two blowers draw a total of 600 watts (300 watts each). I also looked up the specs on the backup unit I have and it will run for 7.5 minutes at the full 600 watts and 20 minutes at 300 watts. As connect at this point in time, it will draw 600 watts.

If home, this will give me enough time to get it going on a generator but my main concern is what would happen if I wasn't home and the condition were set for a full power burn? I am picturing the Fukushima reactors in Japan melting down once outside power for cooling was cut. Is this a major fire hazard or would it just lead to damage of the furnace? How should I handle this?

I have thought about wiring the blowers so that one would run, drawing only 300 watts if the power goes out to give it a longer runtime. Is that a bad idea or not? Anyone have better ideas? Should I invest in a larger battery setup? I have also thought about trying to rig something up that would close the main damper all the way if power is lost for more than a minute or so.

Thank you,

Conor

--modifying UPS units is ususally a deal breaker for warranties, etc, and also they can be made to not work doing it.


with that said...you could add more deep cycle batteries to the input..but...I wouldn't rely on the little built in float charger to maintain reality. Just saying, and disclaimer, do your own research on this..if it was me I would charge them separately with a smart charger, and periodically recharge them. Add enough big glass mat batts and your little fans should run for days, not minutes. Cheapo "float" and "trickle charge" chargers ain't worth spit, IMO. they kinda sorta work, that's it. Batteries have an exact sequence of differing voltages to maintain optimum state, and that requires a smart charger.

I have a small solar system on my RV and modded the furnace fan (propane heater) to run from the four deep cycle 6VDC golf cart batts I use (series and parallel for a 12 VDC system). The rig was originally set up with one or two onboard batteries, now there are six. Two panels. Those two panels ran my computer, GFs TV, lights, and the furnace fan all the time, as required (fridge was dual fuel so it ran propane). It was our only power for a full year. Only very rarely did I have to run the generator or turn the big engine on and charge from the alternator.

Think about it, a cheapo walmart marine battery, under a hundred bucks, will run a trolling motor on a boat for hours. So a set of quality designed to be discharged and used for a long time "real" alternative energy quality batts will work loads longer than that.

Also remember, shallow cycling is your friend on maintaining battery longevity, so always over size your battery bank.

Further disclaimer. Sealed lead acid, which you have inside your UPS unit doesn't need to be vented, unsealed HAS to be vented and sealed off in a battery box, as batteries that are capable of maintenance (adding distilled water, which all the better quality ones require) give off flammable gas.

Or just carry the big batts outside (do not hook them up with the internal battery, get rid of that, you want all the same exact identical batteries) and charge them like in the garage or carport, then haul them back in and hook them back up, that's easy enough. Ya, they are heavy, use a hand truck maybe. Good ones weigh 100 lbs, like that, no joke level.

Another disclaimer..most folks who start looking at things like this, your situation, something that really has to work if the grid is up or not, just go ahead and start building a proper alternative energy rig. I personally would not mod a cheap UPS unit, I just know some people have. I think it is too dangerous and requires actually eliminating some electrical stuff in the circuitry. I would just go ahead get the proper gear and be done with it, for peace of mind. Plus it is just loads easier. You can google arou8nd for opinions from smart guys on modding cheap UPS units..consensus is, for the amount of work involved, it is just easier to get the proper stuff, and a lot more reliable and safer.

You can start with just one circuit in your house for you, the one that runs that furnace.. There's no law says you have to drop 50 grand or whatever and do your whole house all at the same time.

You could *perhaps* look around at your local ISPs for a used rack system larger UPS unit, that would do all you want, plug and play, full controllable interface, all the geeky stuff you could ask for.. Proly need new batts if you bought one, that is a crapshoot, they get changed out a lot, as you probably know..

And you don't need solar panel one or windcharger, grid supplied to charge the battery bank is sufficient for occasional grid outages, and can give you a day to a weeks backup supply for that dual fan setup you run.

So, either way, get the correct sized UPS unit, or start going alternative energy one circuit at a time.

It is *quite* common for people to do this with like normal gas or oil furnaces.

 

[victoria stiles]

Hey. Thanks for the idea of safety dumper. It is a very good and safe idea.

 

[haveawoody]

Or just get one of those heat powered fans that sit on the woodstove that require no power to run.
Ideal thing to have when a power failure happens and ideal to move air in directions that the woodstove doesn't normally move air all the time.
EcoFan Wood Stove Fan - EcoFan Airplus Heat-Powered Wood Stove Fan Review