water heater venting

[flstsi100]

What do i need to know about venting a hot water heater (natural gas)

[Ed Imeduc]

What do you have and what flue. Most are 3" pipe. Run it up hill about a 1/8" per ft. If you have to run a flue up and out .Has to be type B gas vent pipe.

ED ;)

[jansenrpi]

need help with venting an lp fired (tank) water heater that I intend to add to my basement. If I go straight up out of the unit (presumably as high as will allow the rises that follow below), then back about 4 feet (presumably rising an inch or so) and then across my concrete floor "crawl space" 20 feet (presumably rising 5 inches) I find an outside wall that I could go through to presumably put a drip cap of some sorts on.

First question is, would this path be acceptable (I read some places that say so long as you rise between 1/8"-1/4" per foot you can bend as you like but others????). By my math, with an exit that is 102 inches off the floor and a water heater that is say 60 inches off the floor I have over 36" to play with...well lets say I give 18 inches of that to a straight run out of the top of the heater which would still leave me space right)?

Second questions is what type of duct would be required? I would like to avoid power venting (and my impression is that since I have the rise I should not need it). I guess I am learning that direct vent refers to bringing outside air into the room for combusion (should not be necessary as the room has plenty of volume) so does that narrow the choice to b-vent vs. single wall? Not that I trust my brother on all matters but he makes the point that after traveling 24 feet through a nominally 60 degree crawl space it it hard to imagine how the vented gases would be hot enough to require b-vent while going through the outside wall and even if it did could I put non-combustable material around it for this very short stretch of low clearance?

Also do I need to do anything special with the drip cap where I come to the outside at an almost horizontal level (this is a visible portion of the house so I would like to do something that won't make my wife tooooo unhappy but is ultimately safe....there is already a dryer vent and a jenn-aire vent there but I am not sure I need something more substantial.

THANKS

NOTE I EDITED THE MESSAGE TO FOCUS MY QUESTIONS BETTER AFTER TOUGH594 ANSWERED SOME OF THEM (e.g. regarding direct vent and power vent).

[594tough]

Several good question here.

1. Direct vent is a special designed unit which vents horizontally through the wall, AND supplies combustion air directly through an inlet pipe, also coming from outside the structure.

2. A power vent is a fan powered vent system.

3. B-vent is a design of flue pipe for gas burning appliances ( NOT direct vent). Because it has an inner and outer skin, it is rated for minimum clearance to any combustible material of 1".

4. single wall galvanized vent pipe is just that. It has a minmum allowed clearance to any combustible material ( that includes drywall) of 6".



I hope for some responses from others on this next issue: I thought that the minumum slope for b-vent or single wall waas 45º. Also that it must terminate in a vertical direction, not through the wall. Help me out on this one.