Exhaust venting

[greenbikemike]

Last winter at my friend's house,her furnace quit on twice[real cold here last year] I checked everything and it turned out to be the exhaust vent from the furance is about 1 1/2' off the ground and ice would form under it and shut down her furance,clear it away,everything is fine,but a PITA to stay on top of.
The pipe comes out of the house and 90's down,[that's the problem] so i was going to cut it and 90 it up a foot and then out 4-5" then 90 back down.But I'm thinking that water vapor will roll back down the pipe and freeze and be more of a problem....or maybe a 45 it so it shoots out and not right down,not sure bout code,but I've seen some go straight out....so any idea's?.....any and all welcome,
thanks
Greenbikemike

 

[greenbikemike]

Nothing?......I was counting on you guys to steer me in the right direction....I just don't want to do anything thats not up to code. I know that my orginal plan is wrong,up will make it worse,so after looking at it again,and looking at mine,I think just cutting the 90 off and put a 90 back on it and angle it sideways and slightly downward is the way to go.....if I'm missing something,please let me know.....I don't want her to have any problems.....because then they'll be MY problems,and I have enough of my own....thanks for any info about this,
Greenbikemike

 

[brewchief]

Up a foot and straight out would be my preference, furnace instructions will have detailed information on the termination. Make sure you don't have to many 90s, instructions will have a chart for length and number of 90s or 45s for a given pipe size. What brand and model furnace?

 

[Falcon67]

The vent notes on the Big Dawg heater I'm looking at require at least 12" straight out from the heater, then if you 90, there needs to be a clean out. The pipe out from the heater requires a 1/4" per foot slope. It also says that 90 degree bends in 4" pipe use up 5' of effective length and max equivalent run is 30'. There should be similar requirements listed somewhere for the heater you're working on.

 

[greenbikemike]

Up a foot and straight out would be my preference, furnace instructions will have detailed information on the termination. Make sure you don't have to many 90s, instructions will have a chart for length and number of 90s or 45s for a given pipe size. What brand and model furnace?

Thats what my first plan was,but I think that water would run back down that foot and sit in the elbow and really cause a problem.This furnance has been fine for 7-8 years,this last winter is the only time she said shes had any problems,it was real cold and windy with alot of snow,so I'm going to just cut it and put angle a 90 with it pointed slightly down.
Thanks for the replies...keep 'em coming if you have any ideas,

Greenbikemike

 

[Mike007]

Thats what my first plan was,but I think that water would run back down that foot and sit in the elbow and really cause a problem.This furnance has been fine for 7-8 years,this last winter is the only time she said shes had any problems,it was real cold and windy with alot of snow,so I'm going to just cut it and put angle a 90 with it pointed slightly down.
Thanks for the replies...keep 'em coming if you have any ideas,

Greenbikemike

You really need to look at the instruction manual for that appliance as Brewchief pointed out. Since you mentioned code, doing anything other then what the manufacturer specs will not be code compliant. If you don't have the manual, most are available online if you have the model and serial number.

 

[brewchief]

I've done tons of jobs that we had to go up and then out, never have any issues as long as the vent slopes back to furnace as it should. If we have a large amount of pipe outside like under a deck we put foam pipe insulation on it to keep it warmer and reduce the chance of freezing.

 

[greenbikemike]

You really need to look at the instruction manual for that appliance as Brewchief pointed out. Since you mentioned code, doing anything other then what the manufacturer specs will not be code compliant. If you don't have the manual, most are available online if you have the model and serial number.

I'll see if I can find one,thanks

I've done tons of jobs that we had to go up and then out, never have any issues as long as the vent slopes back to furnace as it should. If we have a large amount of pipe outside like under a deck we put foam pipe insulation on it to keep it warmer and reduce the chance of freezing.

This does have about a 6' run that comes straight out of the basement and into a post and beam floor that is insulated and closed in and then out the siding,I just think that any water vapor will freeze in a big hurry.Hell last year I took a shirt right out of my washer and in 2 minutes,it was froze solid!

Thanks for the replies,
Greenbikemike

 

[sms1974]

Hack the 90 off and stick a street 45 on the end that way it blows a bit out away from the house... I typically use a termination plate like this one

http://www.ebay.com/itm/Condensing-Gas-Furnace-Nordyne-Side-Wall-2-inch-Vent-Kit-/351015379362?pt=Air_Conditioner&hash=item51ba25a1a2