What Boiler Can I Power Vent?

 
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Greyhound
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Post by Greyhound » Tue. Mar. 25, 2008 12:48 am

I'm certainly no expert, but basic differences are. PV is negative pressure, and DV is positive pressure. DV pipes have to be well sealed at all joints, yes, it goes out the wall. I also believe that DV usually has combustion air coming in within the same pipe, outside ring of pipe if I recall correctly.

Any of this that is not correct, I'm sure someone will point out for us. ;)

 
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Post by LsFarm » Tue. Mar. 25, 2008 8:41 am

Hi pret, personally I would not PV an AHS or AA boiler... they need a slight draft over the fire when the boiler is not running. The inspection port door opens with a ~1" gap when the boiler's motor/fan is not running, and there must be some slight draft to pull the combustion gasses off the fire and out of the firepot..

This means a power vent must run full time.. this to me would be unacceptable.. And, if the PV failed, there would be combustion gasses in the house.

You can create a real chimney, even a poor chimney will work with the AA or AHS. A short SS or Masonry chimney will create the .02-.,03" draft needed when the fire is idling... When the boiler's motor/fan is running, it is like a DV unit, the flue pipes are under pressure, and not much of a chimney is required,, the combustion gasses are forced out and up..

I'd figure out a way to put in some kind of real chimney, even if it wouldn't work with a hand fired, it will work with the AHS/AA boiler

Greg L
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Yanche
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Post by Yanche » Tue. Mar. 25, 2008 10:18 am

LsFarm wrote:Hi pret, personally I would not PV an AHS or AA boiler... they need a slight draft over the fire when the boiler is not running. The inspection port door opens with a ~1" gap when the boiler's motor/fan is not running, and there must be some slight draft to pull the combustion gasses off the fire and out of the firepot.
But with some new engineering design I think you could successfully and safely power vent an AHS or A-A boiler. Replace the flapper door with an blower that provides the required pressure to exhaust the idle fire combustion gases. Since this blower will have a much lower electric power consumption than the factory internal combustion blower it could be powered by a reasonable sized UPS when utility electric power fails. Any such add-on would move the flapper door equivalent to the inlet of the new idle fire blower. With careful design and analysis I would think you could get a safety lab testing approval for such a system.

 
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Post by LsFarm » Wed. Mar. 26, 2008 2:16 am

Hi Yanche,, much easier for me to build a 16' chimney than experiment with possible CO in the house,, now outdoors?? Sure, I'd try it.

Greg


 
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Yanche
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Post by Yanche » Wed. Mar. 26, 2008 12:43 pm

LsFarm wrote:Hi Yanche,, much easier for me to build a 16' chimney than experiment with possible CO in the house,, now outdoors?? Sure, I'd try it.

Greg
I agree it's easier and far safer to use a chimney flue. Several years ago Jeff at AHS asked me if I know of any testing labs that could certify the coal gun. The conversation was in the context of direct venting. I couldn't help with any suggestions but it got me to thinking about how I would do it. My suggestion to have individual exhaust systems for idle fire and production fire conditions is in my way of thinking what's needed for a fail safe design. I admit I don't know much about safety code criteria for CO leakage in any power vent design. But it is certainly more difficult in a boiler or furnace where the volume of the fire is much larger. At the time Jeff was looking to expand his sales and felt a direct vent coal gun would to that. My point is that it might be possible to do it safely. It's up to the manufacturer to step up, produce a design and get the safety approval testing done. With the exception of the Coaltrol, the residential coal stoves, boiler and furnaces are still 50+ year old designs. Nothing wrong with that but it excludes sales of large central heating units to people who don't or can't have a chimney.

We have an energy crisis looming in this country that is not being addressed. All of us coal burners have solved our personal energy crisis (cost) but we are a pittance in the overall solution. For the life of me I can't understand why the coal appliance manufactures have not gotten together formed a trade association, research council, etc. to promote Anthracite Coal for residential heating. Sure coal is a dirty name in the public eye, but that's Bitumimous coal. Most don't know the difference. When you realize that 2/3 of the BTU content in coal is wasted when you burn coal to make electricty any reasonable person would look for a better way that uses the energy more wisely. Combine that with the fact that it's a domestic product, provides work here and keeps capital here it's a no brainer. Where's the leadership? Oh, I know it's more important to talk about the pastor, the hooker, gun rights or ethnic fears. End of rant. :-)

 
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Post by coalkirk » Wed. Mar. 26, 2008 4:55 pm

There is a chain of 3 hardware stores in my area that devote over 50% of their floor space to fireplaces, stoves, etc. They feature gas fireplaces and pellet stoves. The sell Quarafire, Harman and I think one other brand. They do alot of advertising. There's not a single coal burning device in their stores. They will order a coal stove, boiler etc. but don't advertise or display any coal devices. I think they are misjudging the market.

 
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Post by Complete Heat » Mon. Mar. 31, 2008 9:54 pm

You can order a Keystoker boiler that is power vented. It is a factory option, and they run great. I have a couple of customers that are running them with great results. If you lose power a lot, you may want to consider a battery back-up. There are some great back-up systems out there for about $400. If you don't have a battery back-up, and lose power, the stove will shut down, and yes you will get some exhaust gasses in the house, but not enough to do damage. Open the windows, and you will be fine. The factory installed system has a fume switch built in to the system, so should the vent fail, it will shut down the stove. the largest boiler that can be power vented from Keystoker is the KA-6, which can easily handle a 4,000 sq. ft. home and comes standard with a 300 gph domestic hot water coil. While a chimney is a better solution, it is also a more expensive solution, and in some cases will detract from the appearance of the house. I installed a Class A chimney for my Alaska 140, but I put it through the house (part of the laundry room and a closet upstairs), and it comes through the roof at the back of the house so you can't see it from the road. That being said, that install would cost about $3,000 for the pipe and labor if you paid someone to do the work, and you haven't even touched the cost of the furnace. The power vent option is about a $600 option, and the cost to install is minimal.

Mike

 
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Post by pret » Tue. Apr. 01, 2008 8:51 am

My brother is not a forum member, although I've encouraged him to take a look at the wealth of expertise and knowledge on the site - he's a busy dad with four small boys. Anyway - I'm keeping him abreast of these posts - and I thank you all for your time. Although his home is large, the heat loss is minimal. He has burned less than 400 gallons of oil this heating season! With the basement, the house approaches 4000 if not breaches it. He lives in Southern Lancaster County - Central to Eastern Pa. Power outages are minimal - only when a large ice storm comes through... Of the Keystoker models, which would suite his needs? It seems like he would burn less than 3 tons including the domestic hot water in the summer.

A little different subject: many of you know that I've been waiting to build a house! Well, the land has been subdivided and we plan to break ground in the middle of April. This means... AHS in the BASEMENT come fall. I've been waiting for probably 18 months beyond what I was told initially regarding when I would be able to build. It's kind of like when the power goes out and you call the power company and they tell you it'll be on at 6pm... you call at 6:15pm and then the recording has been changed to 7pm, and of course this continues till 8pm the next evening. All that aside, I'm happy to be moving forward with the project. Soon my tag phrase at the bottom of my post will read... heating with anthracite till kingdom comes (AHS)!


 
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Post by cww » Tue. Apr. 01, 2008 11:52 am

When I purchased my Keystoker KA-6 (144,000 btu) about 4 years ago I could purchase a chimney vented unit or a power vented unit. Chose the chimney vent since there was a good one in the house. Otherwise would have purchased the power vent model.

 
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Post by BugsyR » Tue. Apr. 01, 2008 12:08 pm

Can he build an outdoor boiler room and pipe it in? Greg...don't you do the same?

Reason why I ask is because I am considering this for the distant future. Outdoor boiler room with large coal bin with easy access for coal delivery. Only question I ask myself now is...if boiler room is outside, how high must the chimney be?

(if you're laughing at the questions...consider my signature... :lol: )

 
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Post by LsFarm » Tue. Apr. 01, 2008 1:33 pm

Yes, I have a remote boiler building. My chimney rises about 3' above the peak of the roof, probably a total of 14-16' of chimney... I'd have to go out and count block to be accurate..

Most of the time my manometer shows a .02-.03" draw, this is with the AA260's exhaust keeping the chimney warm.. When the AA is running, I see the same draft, even though the AA's fan for a second or two will create a 'zero' draft reading, but it is only for a second or so, then I see the steady .02-.03" of draft

Today, the wind is howling, 25mph gusting to 40mph+ the manometer is showing .05" and the barometric damper is controlling it between .05-.06" with the higher gusts...

So for an outbuilding, build the chimney for it's height, and location.. the nice thing about a remote building, is no one is living in it.. so if there is a back draft, or occastional poor draft, no one's health is at risk.

Greg L

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