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Anonymous
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# Posted: 21 Jan 2010 04:50pm
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I have a 15x20 cabin with a ventless wall heater. We have barn siding with no insulation. We will eventually insulate it but for now we need to figure out a way to vent the cabin so the heater does not go out in the middle of the night. We have opened windows before but when it's gets 0 degrees outside the windows freeze shut so we can't open them. I saw an article on hear where a gentleman vented his cabin with dryer vents and a j trap for a pipe. Can anyone comment on this or offer me a solution. We have no soffit either.
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Moontreeranch
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# Posted: 23 Jan 2010 11:28am - Edited by: Moontreeranch
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it sounds like something else is going on...drafts perhaps. If the heater is going out due to lack of oxygen...then you are at risk inside. I would check out the heater first give it a turn up so to speak..it might have some fouling in the combustion chamber...is it an infrared radiant or more like a typical rv forced air system.
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Anonymous
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# Posted: 28 Jan 2010 07:30am
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It is a ventless wall heater with blue flames. I've had it tuned up. The reason it shuts off is because it's doing it's job and keeping it safe becasue of low oxygen. I'm going to try the vent system that Josh (a member suggested). Dryer vent on outside with dryer vent hose coming down close to furnace with a j in it. This shoud bring in freshe air and not let to much heat escape. We don't have any soffit or ridge vent so I'm looking to keep some fresh air in the cabin so the heater stays on all the time.
Any other suggestions would be greatly appreciated.
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lawnjocky
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# Posted: 28 Jan 2010 04:57pm
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Call the heater manufacturer. Codes have requirements for combustion air venting for gas fires appliances. There are also restrictions on using them in sleeping area. It may be that your heater is shutting down because it has a sensor for the poisonous combustion byproducts and that sensor is saving your life. It is nothing to half-ass. This can kill you if you are not careful.
Jocko
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Moontreeranch
Member
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# Posted: 29 Jan 2010 03:04pm
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most small gas heaters use a double tube as part of the system, exhaust gas flow out the center while inlet / combustion air flows in by the out "chamber" of the pipe.
While true vent less, have no such pipe at all..here is link to some concerns with these
http://quazen.com/shopping/home-and-garden/heating-with-ventless-gas-heaters/
For an easier install, a simple short run of PVC or ABS plumbing pipe might be easier to install. A 2" hole saw and a few feet of ABS would be way cheaper to buy, you could put one low near the stove and one high up near the roof opposite side of the room perhaps..pick up an elbow and a couple caps...so you can cap the line when its not being used, to keep critters out or in summer etc ....this will be way more robust than dyer vent, simple caulk can fix it in the wall. If you need a larger vent then you could go the dryer vent route.
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Anonymous
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# Posted: 31 Jan 2010 04:56pm
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I tried the venting system by installing a 4" vent and using a dryer hose with a j trap in it. It still did not work. Can anyone help me here. Should I put another vent on the opposite wall or in the roof to suck the air through.
Looking for any recommendations.
Thanks
Vance
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Moontreeranch
Member
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# Posted: 31 Jan 2010 05:39pm
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not sure why you put in the J trap
With just a single "port" air exchange in the cabin will be minimal...if you can visualize a single pipe 4" in diameter closed on one end that is full of smoke...blowing in the open end does not clear the smoke very well at all. if a small 1" hole is made in the capped end and the test repeated it will clear much faster.
having a vent up high will allow natural convection to "pull" air in through the lower vent...as heat rises and goes out the upper port.
it is the same principle that some folks use when starting a fire in a older poorly designed fire place...they open a window or crack a door to allow fresh air in as a thermal draft is established in the chimney...once enough heat has built up and it stars to draw properly they can shut the window or door. Otherwise the room fills with smoke because no "flow" is happening in the flue.
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Anonymous
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# Posted: 31 Jan 2010 07:29pm
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Thank you,
Any recommendations on where to put the other hole. In roof or opposite wall up high.
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Moontreeranch
Member
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# Posted: 1 Feb 2010 10:15am
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I would stay in the wall...the fewer roof penetrations the better. A location near the heater would have the heat that rises up from the heater adding to the "convective flow"
let us know how it turns out.
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Anonymous
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# Posted: 1 Feb 2010 12:31pm
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I currently have a 4" hole about 4 feet above the heater that I can connect a pipe to make it lower. Shall I put another hole on that same wall or go to the other side of the cabin with a 4" hole. Would it work if we open one of the small windows in the loft when we sleep. Trying to save some $ and make it work. We are also having alot of condensation issues. Our plan is to wrap the cabin in tyvek and issulate inside. Probably won't put anything inside as far as drywall or paneling for a yr or so. Any thoughts on that?
Thanks so much for your ideas.
Vance
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Moontreeranch
Member
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# Posted: 1 Feb 2010 01:27pm - Edited by: Moontreeranch
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How close to the heater is the new 4" hole that you already put in? Ideally it should be below the heater to "sweep" the CO (which is heavier than air) up via convection (when the window is cracked)
testing with a window in the loft sounds great...less $$ and holes in your cabin:)
the condensation is an unfortunate by product of the heater...that propane is a hydrocarbon...if you remember from basic chemistry when Hydrocarbons are burned..the by products are CO2 and water...if the combustion is less than Ideal then some CO is produced...plus you are adding to it by breathing, cooking etc.
part of your condensation problem is you are still uninsulated...the moist cabin air is condensing on the cold exterior surfaces.....the lack of insulation is also contributing to your heater problem because it is working so much harder to keep the place warm. Insulation is fairly cheap and you can get it installed quickly...If you are up north or east a vapor barrier on the inside (warm side) of the insulation will help a lot...the dry wall or paneling can co on later...just be cautious of fire near the paper backing on insulation if you go that route...I like using the encapsulated insulation...its basically regular insulation in a plastic bag...nicer to install...no itchy. We saw a HUGE change once we insulated...passive solar heats during the day...even with outside temps in the teens.
Our wood stove sends the combustion gases up the stove pipe...with the moisture from its combustion also going up and out. The relatively dry radiant heat of the cast iron, does not contribute to any moisture issues.
Tyvek house wrap is used to prevent rain and such from getting in it is considered vapor permeable. A 6 mil poly vapor barrier on the inside will reduce the condensation effects of humid inside air from condensing inside the insulation as it reaches the colder outside.
If you still continue to have moisture trouble and you are "on grid" a small bathroom type vent could be used to power vent your place, if your off grid a small DC fan via solar could move some air/ moisture.
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Anonymous
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# Posted: 1 Feb 2010 03:43pm
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Thank you so much Moontreeranch. I'm getting iso this week. I can run my hose down so the air is coming in below the heater.
Do you reccomend something other than Tyvek for the outside wrap.
Thanks again
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Moontreeranch
Member
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# Posted: 1 Feb 2010 03:55pm
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Tyvek is great for outside house wrap..use it
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