Exterior vent placement

[anemone]

I will be having my ancient gas furnace replaced by a high efficiency gas furnace (Trane, XR90). Part of the installation includes venting to the outside. The big question: what factors are used to figure out where the vent should be? I can't find any info on this. Is the vent loud or ugly? How big is it? Can I get a picture BEFORE the installers come?

I realize that the furnace vent cannot be near my dryer vents, so that rules out one side of the house (the dryer vent is basically in the middle of my house and I think the code is that the vents should be at least 10 feet away). Since I don't think it should vent to the front, that leaves two sides: the back or the remaining side.

The remaining side of the house abuts my driveway. Is there any reason that would make this a bad choice? My concern is that it would be in full view every time I enter the house. That leaves the back of the house. The pipe would then have to go underneath all the beams of basement ceiling - is this viable?

Also.... it's going to be around 20-30 degrees here - I'm assuming the installation will be done in one day & I will have heat that night. Should I worry about this or double check with the installer? I certainly don't want frozen pipes!!

Thanks so much!

[Toolpusher]

Your pipes won't freeze at those temps for 1 night.

The exhust is not loud, Most times it can go about anywhere. If you have concerns about it being an eye sore
Talk to your installtion crew before they begain.

I try to go over that with customers during the estimate,So no-one gets surprised later.

[mwsart]

The only codes I know of are that exhaust vents need to be more than 5' from an openable window. There are no codes that say you can't place the vent near a dryer vent. If your installer is doing a normal job the intake and exhaust will be in the same termination... about 4-5" diameter and sticks out 6-7". We operate under UBC and UMC rules here... though I don't believe IBC is much different.

[wallynut]

The PVC vent size is determined by Furnace size [BTUH]and the distance from furnace to outside,Standard is 2" or 3" but all this information comes with installation instructions. Also distance from windows,Doors etc.
The vent normaly pitches back to furnace.I use a lot of 50,000 BTUH condensing units and can run 2" PVC 40' with Four 90s.

[anemone]

Thanks for all the replies. If the vent sticks out 6-7", I don't think the driveway side is a good idea. It would be *extremely* noticeable. But, if it's true about the fact that it needs to be 5' from an openable window, then that's a problem since there are basement windows on all sides except the front.

I'm going to search for online installation instructions; if anyone knows a site, I'd appreciate any help. I agree with one poster that it's best to have "no suprises", but I sort of feel I'm doing this in the dark. I hate to do this, but maybe I should ask the rep to return before the installation so that this can be cleared up. Is that being really pushy?

[amickracing]

Do a search for Bayvent terminations. It's basically a wall termination that Trane makes, it only sticks out 2 inches (roughly) from the side of the house), looks really nice and works great.

Ask the installers/salesman about them, I'm pretty sure they should be able to use one.

[mo-flo]

CAN YOU GO UP THRU ROOF?....sorry bout the caps.

[fat eddy]

I thought it was normally 7' high if on a walkway or driveway, 3' from any other penetration, or appliance ( a\c unit or meter gas\electric and one foot above expected snowfall level. expected snowfall level here is 18 " so 30 " off the ground before you even start. Or abandon the chimney and use it as a chase.

[jjb]

I'm considering moving my furnace, which would require a hi efficiency due to no chimney where I want to move it to. However, venting through the closest wall at the new location would be under a 3' high semi-enclosed deck. I found the below venting instructions for a direct vent boiler, and assume they apply to any direct vent furnace. Are they any simple external solutions for this, or is this a non-starter?



Do not wrap or insulate vent pipe and fittings.

Do not extend exposed vent pipe outside of building. Condensate could
freeze and block vent pipe.

A gas vent extending through an exterior wall shall not
terminate adjacent to the wall or below building
extensions such as eaves, parapets, balconies or decks.

[johnsp]

No go venting under a deck. Get the install manual for that model furnace. Every 90% efficent appliance is different. Don't go by a boiler manual.

[jjb]

I haven't selected a new furnace yet (because I don't know if I can relocate it yet), but I'm not sure that a furnace install manual would say how I would solve my deck problem - I expect it would say "don't do it" or "consult local building codes".

I've found the following product, which is a snorkel for increasing the termination height by up to 3', external to the house. I don't have a problem cutting a hole in my deck. Would this device would be compatible with a (any) 90% furnace? If so, are these things common enough that any HVAC guy would know about them?

http://www.selkirkinc.com/pdfs/chim/DirectTemp.pdf

[jjb]

I haven't selected a new furnace yet (because I don't know if I can relocate it yet), but I'm not sure that a furnace install manual would say how I would solve my deck problem - I expect it would say "don't do it" or "consult local building codes".

I've found the following product, which is a snorkel for increasing the termination height by up to 3', external to the house. I don't have a problem cutting a hole in my deck. Would this device would be compatible with a (any) 90% furnace? If so, are these things common enough that any HVAC guy would know about them?

http://www.selkirkinc.com/pdfs/chim/DirectTemp.pdf

[Al Gregory]

Do u get alot of snow there. I wish I could find the link but 4 people in Plymouth Mass were found half dead in their house after their vent became blocked by snow last month. One of the children died later in the hospital. Now around here there is lots of talk about revamping the previous codes

[amickracing]

Just curious, but if it's a 90% furnace, with both exhaust and intake being pulled from outside. If the exhaust froze up, how would the pressure switch make and let the next step come on?

If it was a 80% or maybe (big maybe) a 90% pulling freshair from inside, I could see it happening... maybe.

Just wondering, not doubting you at all.

[mo-flo]

even if it did make you would think roll-out or venter limit safety would trip......must of been natural draft..older unit or somethin'..?

[docholiday]

I didnt rerad anything about that case but unless it was vented incorrectlty or safties were bypassed or defeated somehow, it wouldnt have happened.

As for the vent. You know its part of the system, I am sure the installers will discuss your options and together you and they can select a place where it is less obtrusive and safe. The more difficult you make this, the more likley you are to have a problem. There are limits to what you can do and I personally dont suggest testing the vent tables by adding a bunch of elbows or extending it under the deck.

Find a closet and go through the roof.

[wallynut]

First off all those pressure switches are Vacume switches on condensing units that I have put in,and would stay in open position if exhaust were plugged.
Unit will not operate. [Safety]
Also rollout [Double safety]

[Al Gregory]

I understand the house was two years old. I have a friend who is a Captain on the Fire Dept and I guess there is alot of talking being done about direct venting. They said they just go by manufactuers specs at the moment but now snowfall amounts are going to become a bigger factor. All i could get was it was a natural gas hot air furnace vented out the side wall. I dont know if it was 80 or 90%

From what I remember from the news story. The husband worked for the town and was out plowing snow. When he came home the whole family (wife & 3 kids) were found unconscios in the house. They were air lifted to Boston and put in a atmospheric chamber. One of the children died.

[anemone]

Just giving an update: the furnace was successfully installed. After seeing the vent, I decided it should go on the back wall since it was pretty big. The installers said the best place would be where one of my basement windows was, so they boarded that up & put the vent through that. I'll paint it in the spring. I'm very happy with the vent placement - it's sort of behind a bush and thus is not really noticeable. Thanks to everyone for their replies.

Just passing this along (since I had no idea): forced hot air gas furnaces are closed systems. There is a slight, but real possibility that the heater exchange can crack. If it does, carbon monoxide literally pours from the furnace, through the vents, and into your rooms; it can fairly quickly be a threatening situation. Both the installers and a plumber said that if you have a forced hot air furnace, you should *definitely* get one carbon monoxide detector for each floor. You all probably know this, but it was news to me! And I've had a forced hot air furnace for over 20 years with no CO2 detector!!

[wallynut]

The sugestion you have carbon monoxide detectors in your home is a great idea but I question your contractors statement that carbon monoxide will poor in if heat exchanger cracks.
These new Condensing furnaces are designed so inducer fan is on downstream side of heat exchangers which will create suction on Both heat exchangers not pressure if a crack were to occur.