What boiler can I power vent?

What boiler can I power vent?

PostBy: pret On: Sat Mar 22, 2008 11:19 am

Is there a boiler, like the EFM or the Harman Vf3000 that can be power vented? I'm asking for my brother who has a 3000+ sq ft home not included full finished basement looking to heat with coal. No chimney or place to put one... oil furnace is power vented. Would like to heat with coal boiler in tandem with the oil furnace... using the necessary heat exchanger, etc. Thanks.
pret
 

Re: What boiler can I power vent?

PostBy: stoker-man On: Sat Mar 22, 2008 2:37 pm

You cannot power vent an efm coal boiler because the fire is always producing CO or some sort of gas. If you were to install a continuous draft inducer, or something similar, you might be able to do it, but you'd probably use more coal. I think Tjerlund makes such a product, but expect to replace it every few years.

A power venter is made for fuel that stops combusting when the blower shuts down.
stoker-man
 
Hand Fed Coal Boiler: 1981 efm wcb-24 in use 365 days a year
Coal Size/Type: Anthracite/Chestnut
Other Heating: Hearthstone wood stove

Re: What boiler can I power vent?

PostBy: Hammer8 On: Sat Mar 22, 2008 3:38 pm

The SWG power vent I have connected to my stoker runs all the time with a safety switch so that in the event the power vent would fail, electricity is cut to the coal feed and combustion fan killing the fire. Why couldn't the same system be used with a boiler? Is it because of the boiler cycling to meet demand rather than maintaining a more consistant sized fire? The vent and barometric can be adjusted to provide proper draft at full fire.
Hammer8
 
Stove/Furnace Make: Alaska
Stove/Furnace Model: Kodiak Stoker with power vent

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Re: What boiler can I power vent?

PostBy: stoker-man On: Sat Mar 22, 2008 6:01 pm

That's an OK setup because there is a safety disconnect involved. It's similar to a draft inducer setup I mentioned. But, think about the air constantly blowing over the coal bed and being drawn out of the house. There might be other reasons I'm not recalling.
stoker-man
 
Hand Fed Coal Boiler: 1981 efm wcb-24 in use 365 days a year
Coal Size/Type: Anthracite/Chestnut
Other Heating: Hearthstone wood stove

Re: What boiler can I power vent?

PostBy: pret On: Sat Mar 22, 2008 6:47 pm

Is the issue safety as opposed to code violations?
pret
 

Re: What boiler can I power vent?

PostBy: stoker-man On: Sat Mar 22, 2008 7:06 pm

I'm not up on all the codes, but I know that efm doesn't recommend it. But having a continuous draft with a safety interlock and a good CO detector, should satisfy the codes. Check out Tjerlund and Field draft fans for a possible application.
stoker-man
 
Hand Fed Coal Boiler: 1981 efm wcb-24 in use 365 days a year
Coal Size/Type: Anthracite/Chestnut
Other Heating: Hearthstone wood stove

Re: What boiler can I power vent?

PostBy: Sting On: Sat Mar 22, 2008 8:24 pm

I am doing it - but I am burning a fuel that will go out fairly quickly, and that is going to be an issue if you have a more than short term power failure. I can get a graceful shutdown with the UPS on my http://www.patriot-supply.com/products/ ... m.cfm/4549
but it would take far more battery than I currently stand to keep a coal pile vented till its cool.

Please do not install any power vent that is not UL approved -and please wire it so the UC1 draft proof, protects you from un-vented or reduced draft appliance hi fire.
Sting
 
Other Heating: BurnHAM=NG-gas

Re: What boiler can I power vent?

PostBy: Richard S. On: Sat Mar 22, 2008 10:40 pm

Hammer8 wrote:The SWG power vent I have connected to my stoker runs all the time with a safety switch so that in the event the power vent would fail, electricity is cut to the coal feed and combustion fan killing the fire.


The efm boiler is similar to my Van Wert boiler, it will stay lit for hours once you shut it off if there is good fire going. Can't give you exact time but if I had to guess 4 to 6 hours. I'd imagine that is the reason they won't recommend a power vent.
Richard S.
 
Stoker Coal Boiler: Van Wert VA1200
Coal Size/Type: Buckwheat/Anthracite

Re: What boiler can I power vent?

PostBy: Yanche On: Sat Mar 22, 2008 10:44 pm

pret wrote:Is the issue safety as opposed to code violations?
I know of no coal stoker boiler that is approved for a power vent. The safety issue is indeed the CO production when the power goes out. To get code approval equipment manufactures need certification testing from a testing lab. That's how stoker stove manufactures do it. The fire code then accepts the manufactures code approvals. A stoker stove has a much smaller volume of burning coal compared to a boiler. So when the power goes out, the safety interlocks stops the feed of coal and the existing fire will go out. Apparently, the testing and certification labs have concluded the amount of CO produced by the burning coal, that is now going out because there is no forced combustion air, is acceptable from a safety hazard point of view. I doubt that would be the case in a boiler, since the volume of the burning coal could be rather large especially if the power would go out during a peak demand full fire condition.

That said it would be possible to direct vent a coal boiler depending on the installation location and how much safety engineering you want to be responsible for. One could for example have a battery backup vent system with enough capacity to vent combustion gases until the fire goes completely out. I would look for a boiler that has a small volume of idle fire, like the AHS Coal Gun or A-A Anthratube. There may be others but I'm not familiar with and I'm certainly not familiar with the relative volumes of idle fires. The advantage of the AHS and A-A is that the combustion blower is built-in. You would have to only engineer a idle fire combustion gas system. AHS had a customer that did so by replacing the combustion blower motor with a variable speed drive motor and running the motor on low speed to exhaust idle fire gases. It was NOT installed in a residence and the owner accepted the risks of a no electrical power condition. To the best of my knowledge it did not have a battery backup system.
Yanche
 
Stoker Coal Boiler: Alternate Heating Systems S-130
Coal Size/Type: Anthracite Pea

Re: What boiler can I power vent?

PostBy: Berlin On: Sat Mar 22, 2008 11:43 pm

"No chimney or place to put one... oil furnace is power vented."

what do you mean "no place to put one"? where his home ends do sheer cliffs drop 4,000' into the sea? if not then he can, indeed, install (fairly inexpensively too) an exterior chimney. a block and tile masonry chimney is very simple to put up either inside or outside the home. this would be by far the best and least troublesome way to go.
Berlin
 
Hot Air Coal Stoker Furnace: Will-Burt Combustioneer 77B
Coal Size/Type: Ohio BITUMINOUS pea stoker coal

Re: What boiler can I power vent?

PostBy: Hammer8 On: Sun Mar 23, 2008 8:21 am

it will stay lit for hours once you shut it off if there is good fire going


I didn't realize a boiler would burn that long after shut down. I'm used to turning off the combustion fan to mine and in 15-20 minutes the fire is out. Your style obviously burns with a much deeper bed. It makes me wonder if a PV would be possible with a Keystoker. The grate design is similar to my Alaska and to Leisure Line, but must burn a deep bed also to get the higher BTUs out of it. I'm not trying to argue this to death- just wanting to learn something. I know for a fact that a chimney is the better way, but not always an option.


I am doing it - but I am burning a fuel that will go out fairly quickly


Are you burning corn, wood pellets, or both? Wouldn't there be any concern for creostoe build up on a venting unit burning pellets? I don't have any experience with either.
Last edited by Hammer8 on Sun Mar 23, 2008 9:24 am, edited 2 times in total.
Hammer8
 
Stove/Furnace Make: Alaska
Stove/Furnace Model: Kodiak Stoker with power vent

Re: What boiler can I power vent?

PostBy: Sting On: Sun Mar 23, 2008 9:02 am

Hammer8 wrote:Are you burning corn, wood pellets, or both? Wouldn't there be any concern for creostoe build up on a venting unit burning pellets? I don't have any experience with either.


Both - separately and mixed - The corn products of combustion are cooler and "stickier" they foul even the SS2 impeller quickly.

Another testimonial for draft proof on any solid fuel appliance Image ...


Pellets burn drier and hotter and the impeller is able to "spin off" the soot. So when burning straight corn I find myself pulling the PV guts twice a weeks and marching the contraption outdoors to clean it with Hi pressure air. But thats a silver lining for me - I couldn't clean my 40 foot tall chimney in the same time!!! I stand safely, with both feet on the ground, at all times, for all vent related drama. I just need to extend care to my PV a bit more often than if my appliance were on a chimney - when burning straight corn - so I get around that by burning at least equal portions of corn and pellets - or straight pellets - as corn has increased in price to make pellets now the "cost effective fuel" with the equipment I currently have. The mixed fuel or straight pellets make products of combustion temps regularly above 275 degrees and that also is a key to keeping the PV clear.

AS you may have noted is some of my other posts I am trying to figure out if I can correct that fuel choice oversight.

If I can find a stoker engine to repower my corn/pellet boiler (or sell this one and find a replacement) I will think very seriously about moving it to my chimney and power venting my NG backup boiler as I think I can brush my chimney with a snake from the basement to daylight - but thats a topic for another thread. Today I wouldn't PV anything but the Harmon appliance as it appears to be higher tech - could benefit from a constant consistent draft - and is sized that the SS2 should be able to handle it. Thats another concern you will need to watch - the SS2 - one of the only affordable (residential) impeller style PV's - will not be big enough for many other choices.
Sting
 
Other Heating: BurnHAM=NG-gas

Re: What boiler can I power vent?

PostBy: Highlander On: Sun Mar 23, 2008 9:20 am

Keystoker offers the KAA2 with a factory installed power vent. The KAA2 uses the same stoker assembly as their stoves which can also be had as direct vent. A few of the forum members have them and like it.

I had debated using a SWG power vent with my VF3K, but decided that the power required to run it 24/7 and the maintenance it would require were not worth the effort and put up an insulated SS chimney instead.
Highlander
 
Stoker Coal Boiler: Harman VF3000
Hand Fed Coal Stove: Vermont Castings Resolute
Coal Size/Type: Rice
Stove/Furnace Make: Harman
Stove/Furnace Model: VF3000 Stoker Boiler

Re: What boiler can I power vent?

PostBy: Richard S. On: Sun Mar 23, 2008 1:47 pm

The efm and my Van Wert use a burn pot or what I describe as a up side down bell, they are both auger fed. The auger feeds the bell from underneath. So yes you do get a pretty deep bed of coal. If its running full tilt probably a good six inches deep and about 1 1/2 foot across .There is most likely a significant amount of unbunred fuel in the bottom of the bell. The keystoker uses a bed type design, not much different than a small stoker really just a big version.
Richard S.
 
Stoker Coal Boiler: Van Wert VA1200
Coal Size/Type: Buckwheat/Anthracite

Re: What boiler can I power vent?

PostBy: pret On: Mon Mar 24, 2008 5:29 pm

Okay... so as Mr. Yanche said, a DV system would be feasible. My brother is interested in the AHS or the AA - he likes the best (just had to say it) in life, so it may work. Could someone speak regarding the general differences between Direct Vent and Power Vent? To guide the responses... is the DV vented out the side of a wall, like a PV?

Thanks...
pret
 

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