Long, but I’ll try to summarize-
Have an old, abonded brick chimney chase no longer used (a small, late 1800’s brick chimney USED to vent HWH and furnace… no longer does, and brick chimney now removed) so basically I have this chase boxed in a wall, runs from opening in basement, through 1st floor, through 2nd floor, temporarily capped with plywood in attic… wold like to install B-vent pipe to re-exhaust furnace & hwh in the chase, through attic, out roof.
I have seen in some new construction it appears a regular sheet metal ducting pipe may have been installed during rough-in, and later the b-vent is slid in that, of course the sheet metal one is larger so the b-vent fits easily and has some room… but I only recall seeing this set-up in a one-story new construction home. Would this idea work/meet code in a two story? have anyone done anything similar?
I’m trying to NOT have to rip open the finished walls to run this.
Thanks!
Replies
I would look at getting a properly sized chimney liner kit for the portion though the "chase". You can make attachments to the appliances with standard galvanized sheet metal (30 ga), though I would recommend the thicker material if you can get it, minimum of 26 ga. You will need a short 18-24" piece of b-vent pipe to go through the roof, a "dale vent" hanger or the like, an adjustable roof flashing, storm collar and a b-vent cap. You will want to seal the opening aroung the vent going into the chase in the basement. Sheet metal with high temp caulk will work for this.
Thx Tim...
I'm asking if we both understood my description... I don't have a brick chimney to put a liner into any longer... the brick chimney USED to be in teh wall, but the bricks are now gone, so it's kind of a closet in the wall (the chase) without any doors into it... a 'boxed in square' in a wall, center of home I should have stated, not on outside wall.
Major idea was the 'regular' sheet metal ductwork say perhaps a 7, 8 or 9" 'pipe/duct', in this chase... and INTO that I'd run b-vent all the way up & out, connect as right/usual in the bsmt t the gas appliances.
I SHOULD HAVE installed teh b-vent years ago when we did have the walls open to remove the bricks.. hence my trying NOT to now.
My concern was reading about fire blocking or the like at each floor stop with the b-vent, again trying to not open the walls.
BobbyT in Illinois - 'da 'burbs of Chicago
Bobby,
Where in "'da 'burbs of Chicago" are you. Makes a difference. I have recently done mechanical engineering work in Sugar Grove, Shaumburg and Geneva. So it depends on which code applies, and when was the house built.
How are the gas appliances currently vented?
Tim
Thx Tim...
LaGrange/LaGrange Park.
The original house was built in 1888...
Currently both the gas furnace & gas water heater are direct/power vented side wall...
The wather heater is made for this, looks just like a reg gas fired one, but with built in power venter, can & does go out PVC side wall.
The furance is about a 90's something model, and when we know the chimney was no good, we went to replace it, but the HVAC guys wondered why, when it wasn't old, and worked... thought we'd have to replace with one of the very high eff models that side-wall with PVC< but these techs said this model could vent (although not pvc) side-wall with a, and forgive me I;m going this from memory, Turgelund/Turgeland vent kit... and they did.
These work, but for quietness on the furance, and piece of mind for powerouttages with hot water, I'd prefer to let them vent up (a b-vent) like the good ole days when they exhaused into a chimney.
Any ideas?
BobbyT in Illinois - 'da 'burbs of Chicago
If the gas water heater is draft induced (i.e. power vented) and the furnace is not (after you remove the Tjernlund draft inducer), you cannot vent them in a common flue. For that matter, it is seldom allowed and never a good idea to common vent any draft induced appliance with another.
If you lose power you will have no heat regardless of the venting of the furnace. The furnace will not fire without the blower available to move air. I know the tjernlunds are noisy, not much to do about that. Depending on the specifics of the water heater, it may not fire without power either. IF you want to common vent these like you describe, you will need to replace the water heater with a "millivolt" type or one with a pilot.
IF you have two gravity vented appliances, then it should be very straight forward to run the b-vent through the space the chimney used to occupy. Typically, depending on the size of the furnace, the venting will be a 3-4-5 configuration. That is 3" from the GWH (usually 40,000 btuh in), 4" from the furnace (up about to 90,000 btuh in) combined via what is commonly referred to as a "water heater tee" which is a 3x4x5 lateral or wye, and 5" b-vent up and out. Keep the b-vent separated from any direct contact with framing, support it at the roof penetration and midway with a "dale vent" hanger. Then at the roof you'll need the cap, storm collar and flashing. There is no need to put the other pipe in the chase. Check out http://www.hartandcooley.com/vent/all_vent.htm for the details.