Other Technical QuestionsDiscussion of other technical topics. Please see the sticky post at the top of the thread listing for specific rules. The rules for this forum are more restrictive than they have been in the past. Topics will expire automatically in 60 days.
The forced air furnace in our shop exhausts through a 3" PVC (it exits the siding, takes a 90 degree bend straight up, then a 90 degree bend back to horizontal, and then extends out about 18" through a straight piece of 3" PVC with the end cut off at a taper), and gets its fresh air through a similar piece of 3" PVC (it comes out, takes a 90 degree bend up, then a 180 degree U to point down at the ground). Both pieces of pipe, with joints, stick out around 30" from the siding.
I understand the rationale behind having some bends on them, but is there a reason they need to be so long? Right now, they look like crap, sticking out like a sore thumb. Is there any other option for dealing with the intake/exhaust that would look a bit more aesthetically pleasing? I can paint the PVC I'm sure, but is there anything I can do first?
I can understand the rationale of extending the exhaust out from the building, to keep the carbon monoxide (CO) away from the structure, but the furnace on my house only sticks out about three inches, so I don't know why yours is out so far. Did you have this installed? If you can find out from the person/company who installed it.
I'm curious as to why your cold air intake is from the outside. Is the structure so tight that make up air can't/won't come in?
No concerns about the heated exhaust going through PVC? Usually that's double-insulated sheet metal
He has what's called a "condensing" furnace. They're very efficient because they extract most of the heat of combustion and use it to heat the house. There's a big heat exhanger that recovers most of the waste heat that used to go up the chimmney. The exhaust goes from 1800 to 2000 degrees F, down to around 150 to 200 degrees. Cool enough to use PVC. On an old fashioned furnace, the waste heat causes the exhaust to travel quickly, but on a condensing furnace, the exhaust slows way down as it's cooled, so it needs to be pushed out with a fan.
The reason that they use PVC is because the exhaust has a lot of water vapor in it that mixes with the usual sulphur and nitrogen oxides as a result of condensation cycle. This exhaust would quickly corrode standard flue pipe.
As to why his pipes have some many bends in them - no clue
I am guessing the exhaust is so far out from the building so all the caustic gases are away from your siding, flashing, shingles, etc.
__________________
1996 F-250 extended cab long box five speed. Home made Tymar, 203 Stat, 60 gal in bed fuel cell, 315/75's, no muffler, ebpv welded open 3" to 3" DP, Babies. 290K, still chugging, and still smoking when cold.
UPDATED 8/1/08 Replace so far. 1 LUK flywheel+clutch, 2 thermostats, 2 set of brakes, 1 set of calipers, 5 CPS, 3 sets of tires, 2 Transfer pumps, 1 Injector modual, 1 Computer, 2 Alt, 2 sets of batteries, 1 Water pump, 6 Belts, 1 PS hose, 2 Sets ball joints, 2 set u-joints, 2 carrier bearing, 2 Speed sensors, 1 oil pres sender, 1 temp sender, 4 sets of e-break cables, 1 front fuel tank, 2 rear fuel tanks, 2 set of glow plugs, 6 Glow plug relays, Oil galley o-rings, Turbo pedistal o-rings, EBPV o-rings, 3 sets of Injector O-rings, 1 Vac-pump, 1 new carpet.Total $$$ in repairs v/s miles driven = 3.0 cents per mile. Add fuel to that it jumps to 14.8 cents per mile over the life of the truck.
AutoForums.com is the premier network of enthusiast-owned
enthusiast-operated automotive communities.
We operate more than 100 automotive forums where our users consult peers for shopping information and advice, and share
experiences and opinions as a community.
Linear Mode
