vent furnace and WH horizontally
I’ve consulted both of the manuals for my 80+ mid-efficiency forced-air, gas furnace and my natural draft-induced gas WH, and they both indicate I can vent out of the house horizontally if done properly with proper pipe materials and pitch angles.
My question is does anyone have any resources they can point me to for tips and photos for the right way the DIY’er can accomplish this? Ideally, I’d like a way that joins the 2 exhausts in my basement and exits the house in one, clean application.
I am currently vented to a chimney, but I am about to get a new roof and thought, hey, why not remove the chimney and patch up the hole while we’re up there? I don’t care so much about any tear up to the siding as I plan on getting insulation and siding after the roof job. If it matters for code, I live in the SE Michigan area.
Edited 5/28/2005 7:59 pm ET by natepartlan
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I could be wrong, but I know of no natural draft appliances that can vent horizontal.
What make and model?
Some of the installation instructions for 80+ and water heaters indicate that they can be vented out the side with aftermarket draft assist fans.I personally don't think it's a good idea, although the only specific objection I would have is the noise. I see those fans every now and again and they are pretty noisy, and they transmit the noise quite effectively into the house through the floor framing which they are hung from.
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I don't know about furnaces, but there are a number of direct vent water heaters available. And they don't have fans.But the horizontal distances are very limited on the couple that I have looked at the specs on.
If the manufactor says you can do this, you probably can. That dosen't mean that your local code will permit it. You have to find out what gas code they are using; this will also tell you what they want when you twin two flues together. I would suggest that if you do this, invest in a carbon monoxide detector,[the silent killer]. LOL.
Bill and Bob, I agree, but the OP made no mention of fans and it sounds like a standard wh. I think he just wants to stick the vent out a window. Without make and model, I'll bet a beer that he can't (should not)do it.
VERY good point!I was reading "if done properly with proper pipe materials and pitch angles" as including fans, but you're right.Original Poster:If you are thinking of just sticking the flues out of the sidewall without more, don't! The life you lose could be your own!
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The WH is a Rheem, model #PG40T9A. Upon re-reading of the WH manual, it seems to be that I should assume properly pitched horizontal runs TO A CHIMNEY is what they truly intend to say, but it is not quite clear. I will have to call the manufacturer after the holiday.
So this leads me to ask what is the difference in venting combustion exhaust up a chimney vs. out a sidewall above which their are no obstructions (shrubs, roof overhangs, etc.)? I must assume NONE since direct vent and power vent models allow it. Remember, my combustion air (for both furnace and WH) comes from within the house so there is no danger of sucking exhaust air back in for combustion.
If sidewall exhaust is only allowed with direct vent or power vent models, this leads me to ask if anyone makes an add-on kit to convert a traditional venting model? If so, where can I find it?
Or in other words, I do not fully understand the differences between traditional vent and direct vent. Can someone clue me in?
Edited 5/29/2005 1:56 pm ET by natepartlan
I think some research has yielded my answer. Direct-vent has a sealed combustion chamber to prevent backdraftiung of harmful gases (which also necessitates an air inlet system). If you sidewall vent a traditional, atmospheric vent model, you could backdraft CO into the house. *cough, cough*
So to my original question, I can sidewall vent my furnace through proper installation of SS ducts (category III provisions), but my WH will have to wait until I upgrade. Since I just put in the WH within the last 2 years, I will not be able to take down my chimney just yet.
Everyone agree in my deduction?
So far, so good. As stated before, aftermarket fan kits are usually more trouble than they are worth. In addition, if you remove the furnace, the chimney will probably be too big for the water heater, and will require a liner.
>>So to my original question, I can sidewall vent my furnace through proper installation of SS ducts.Nope - not unless local code and the manufacturer specifies it.I've never seen an 80+ installation manual which calls for anything other than venting above the roof.Maybe there are some out there.There is also the issue of CO concentrations outside the house.Draft assisted water heaters mix very large amounts of air in with the flue gases to dilute even very high CO concentrations (and bring the temps down.)90+ furnaces actually pressurize the flue gases and push them out and away from the end of the flue, which I understand is supposed to achieve the same dilution effect, although there are still minimum separation requirements between the flues and any openings in the house (windows, doors, etc.)(& The 90+ flue gases are also very cool - typically 100 - 110 degrees F and they can't be dumped into a chimney.)FWIW, The new design water heaters with the sealed combustion chambers (don't mix them up with the direct vent sealed combustion chamber models) are running awfully hot when right out of the box - often up near the recommended limits for B-vent, leaving little slack for increased flue gas temps as scale builds up in the bottom of the tanksNo one's quite sure what to make of this yet. The few I've tested are running between 500 and 550. Although the b-vent manufacturers won't say what the limit for B-vent is, they generally recommend temps no higher than 525-550.
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