2-3-10 rule

For my own knowledge:

I know this is a defect because of the 2-3-10 rule. If the water heater flue (B-vent) were raised to be 2’ above the furnace (PVC), would there still be a defect? The water heater would draw correctly, and the furnace is sealed combustion.

If it would still be a defect, why?:roll: Both appliances would work properly.

(None of this is in the report - just wrote it up and recommended an HVAC contractor. Just for me.)


Larry gave you a great graphic.

](http://www.nachi.org/forum/f2/would-you-call-up-chimney-69221/)There’s a good discussion and educationat this thread.

Excellent thread (most of it anyway). I didn’t get the meat of it the first time around, most likely because I read it as a disjointed series of posts, along with posts from other threads.

The main thing I got from the informative part was (I think it needs restated):

It is a common misapplication for code users to apply
chimney termination height requirements to vents, thereby
causing vents to extend above roofs much higher than required
in many cases

Thanks, Joe - this is what cleared it up for me.:smiley:

You probably are confusing solid fuel burning appliances with gas venting.

I don’t see a problem in your photo but the installation requirements of the water heater rule.