Go Back   DIY Chatroom Home Improvement Forum > Home Improvement > HVAC

CLICK HERE AND JOIN OUR COMMUNITY TODAY...IT'S FREE!

Reply
 
Thread Tools Search this Thread Display Modes
Old 01-29-2012, 02:18 PM   #1
Member
 
Join Date: Jan 2012
Posts: 39
Share |
Default

New Furnace venting


I wanted to thank the community here for all the help in diagnosing my HVAC issues. I am resigned to replacing my furnace with a hi eff unit but have questions on the install particularly the venting As i have installers give quotes

Due to logistics: windows and other structures it appears the best option may be to use the existing furnace chimney to vent vertically rather than a outside wall. I sense some installers do not want to climb on the roof in this weather

1) How is this done: will the installer run PVC up to the top of the chimney from the furnace so that 2 pipes are visible?

2) do I need a liner as well?

3) what should the ends of the vents look like given the openings will be very close to one another: angled in different directions?

Liberator is offline   Reply With Quote
Old 01-29-2012, 02:36 PM   #2
REP
Member
 
Join Date: Jul 2011
Posts: 615
Default

New Furnace venting


The installation manuel that comes with the particiuliar furnace you purchase will have very exact instructions on its venting and venting termibnations.
Differant companies have differant requirements.It would be very wise to follow those instructions to the letter in order to avoid future problems.
Using the old chimney as a chase is usually allowable and the old chimney needs to be sealed both at the roof and at the start in the basement.
Now if the old chimney will be used to vent the exhisting water heater then you will not be allowed to use it as a chase for the furnace.In that case you could run B-Vent for the water heater using the old chimney as a chase.

REP is offline   Reply With Quote
Old 01-29-2012, 02:46 PM   #3
Hvac Pro
 
Join Date: Nov 2008
Location: Winnipeg, Canada
Posts: 8,986
Default

New Furnace venting


Yep, they must follow the venting info in the manual EXACTLY or it can have pressure switch tripping problems etc. Where I am the gas inspector will literally use those instructions and red tag it if not followed properly. I hear that Ontario is very picky too. They vent them all winter long and climb up on the roof or hire a Pro chimney repair co to do it for them. You cannot vent the water htr into the chimney or it will melt the pipes so an electric one is required or a thru the wall type and that may not work because of your windows issues etc. I would go electric as a thru the wall type may cost $1500 or more and don't last any longer than the basic ones. You can buy a tankless one but they are $2000-3000 and have venting issues as well. The Lennox ones have a very clean neat configuration with the exhaust sticking straight up and one elbow to the side for the intake rather than some dog eared looking setup like some other nameless brands.
__________________
"Cut it twice and it is still too short".

Last edited by yuri; 01-29-2012 at 02:49 PM.
yuri is online now   Reply With Quote
The Following User Says Thank You to yuri For This Useful Post:
ben's plumbing (01-30-2012)
Old 01-29-2012, 02:57 PM   #4
Member
 
Join Date: Jan 2012
Posts: 39
Default

New Furnace venting


Sorry I forgot to mention that I just installed a new electric hot water heater recently so there is no venting required for the tank.

Are vertical venting installs more problematic than side exterior venting for the pressure switches?
Liberator is offline   Reply With Quote
Old 01-29-2012, 02:58 PM   #5
how
Member
 
Join Date: Feb 2011
Location: Vancouver BC
Posts: 1,489
Default

New Furnace venting


hey Yuri
I saw an installation last week that was a few years old that had a single chimney used as a chase for a B vented HWT and the PVC lines for a 90%.
It was a new one on me and I wondered why I hadn't seen it before since it had been inspected, approved and lot's of folks with furnaces in the center of their homes ***** at routing the vent lines through to the outside walls of their homes.

Last edited by how; 01-29-2012 at 03:53 PM.
how is offline   Reply With Quote
Old 01-29-2012, 04:01 PM   #6
REP
Member
 
Join Date: Jul 2011
Posts: 615
Default

New Furnace venting


Hey HOW! Absolutely nothing wrong with b-vent and plastic venting using the old chimney as a chase as long as the 1 inch is maintained between them.
The only problem would be if in an old house the lenth of the vent exceeded the requirement..
REP is offline   Reply With Quote
The Following User Says Thank You to REP For This Useful Post:
ben's plumbing (01-30-2012)
Old 01-29-2012, 04:04 PM   #7
Hvac Pro
 
Join Date: Nov 2008
Location: Winnipeg, Canada
Posts: 8,986
Default

New Furnace venting


I have not seen it done that way as a 4" B vent must be 5" OD and the 2" PVC venting is 2.5" OD so you would need a full 8" chimney which is kinda rare these days. Most have been lined already so that old liner would need removing etc but it do-able if the inspector allows it. Would make for a difficult cap on top to seal it from rain etc especially in your area. That seems to be the biggest drawback is how to seal it at the top. How do U guys do it? Slather silicone around a cap with holes cut in it?
__________________
"Cut it twice and it is still too short".
yuri is online now   Reply With Quote
Old 01-29-2012, 04:05 PM   #8
Hvac Pro
 
Join Date: Nov 2008
Location: Winnipeg, Canada
Posts: 8,986
Default

New Furnace venting


Quote:
Originally Posted by Liberator View Post
Sorry I forgot to mention that I just installed a new electric hot water heater recently so there is no venting required for the tank.

Are vertical venting installs more problematic than side exterior venting for the pressure switches?
Not really but birds can nest up there and who want to climb up there and deal with any blockages later? I avoid vertical venting like the plague.
__________________
"Cut it twice and it is still too short".
yuri is online now   Reply With Quote
Old 01-29-2012, 04:26 PM   #9
how
Member
 
Join Date: Feb 2011
Location: Vancouver BC
Posts: 1,489
Default

New Furnace venting


Hey Yuri
Many homes here already have large overhanging chimney caps to deal with the constant horizontal rain which nicely cover our silicone & metal cap slatherings.
Almost all the 90% are going through the wall for simplicity and reliability.

Last edited by how; 01-29-2012 at 04:29 PM.
how is offline   Reply With Quote
The Following User Says Thank You to how For This Useful Post:
Liberator (01-29-2012)
Old 01-29-2012, 04:36 PM   #10
Hvac Pro
 
Join Date: Nov 2008
Location: Winnipeg, Canada
Posts: 8,986
Default

New Furnace venting


My Cousin lives in Abbotsford and says the rain is a huge issue ( he is a homebuilder ) as it gets in the cracks of stucco and walls rot and they have to put zinc strips on some roofs to prevent moss growing etc. I love visiting BC (went kayaking with the Orcas) etc but prefer my dry but cold climate.

I guess if done properly (unlike the leaky condo scandal yrs ago) you guys can deal with the rain.
__________________
"Cut it twice and it is still too short".
yuri is online now   Reply With Quote
Old 01-29-2012, 04:40 PM   #11
Member
 
Join Date: Feb 2007
Location: NW Ohio
Posts: 804
Default

New Furnace venting


One thing that the OP should keep in mind, in the wrong situation, 90 + vent pipes can and do sometimes form ice balls and freeze, if its side wall vented this is an easy fix.......not so easy when its vented on a roof peak.
Yes a old chimney chase can be used, but only as a final alternative should it be used.
harleyrider is offline   Reply With Quote
Old 01-29-2012, 04:49 PM   #12
Hvac Pro
 
Join Date: Nov 2008
Location: Winnipeg, Canada
Posts: 8,986
Default

New Furnace venting


The high end Lennox SLP mod and the high end Carriers have an ecm ventor fan which can compensate for some of the blockages but not all. Not sure if any other brands have an ecm ventor.
__________________
"Cut it twice and it is still too short".
yuri is online now   Reply With Quote
Old 01-29-2012, 04:51 PM   #13
Member
 
Join Date: Jan 2012
Posts: 39
Default

New Furnace venting


Yes, I have a large new slab overhanging onto of the chimney as a cap. When I look down from the roof into the chimney, there is a 5" aluminum venting coming up partway up the chimeny for the existing furnace.

There is no other liner on the concrete blocked furnace chimney.



Quote:
Originally Posted by how View Post
Hey Yuri
Many homes here already have large overhanging chimney caps to deal with the constant horizontal rain which nicely cover our silicone & metal cap slatherings.
Almost all the 90% are going through the wall for simplicity and reliability.
Liberator is offline   Reply With Quote
Old 01-29-2012, 04:54 PM   #14
An old Tradesmen
 
Join Date: Oct 2008
Location: PA
Posts: 24,486
Default

New Furnace venting


York mod's have VS ECM venters.
beenthere is offline   Reply With Quote
Old 01-29-2012, 05:19 PM   #15
Hvac Pro
 
Join Date: Nov 2008
Location: Winnipeg, Canada
Posts: 8,986
Default

New Furnace venting


Quote:
Originally Posted by Liberator View Post
Yes, I have a large new slab overhanging onto of the chimney as a cap. When I look down from the roof into the chimney, there is a 5" aluminum venting coming up partway up the chimeny for the existing furnace.

There is no other liner on the concrete blocked furnace chimney.
Partway?? Hopefully the chimney is perfectly straight/vertical and NOT offset or you will have a HUGE problem. If offset then they have to bust open the chimney from inside or outside the house to glue and offset the pipes. beenthere and done that and it ain't pretty.

__________________
"Cut it twice and it is still too short".
yuri is online now   Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Natural Gas Cost For Furnace 1 Hour Run Time hammerlane HVAC 15 11-11-2013 10:34 AM
Furnace venting questions Mastiff HVAC 9 12-05-2012 05:51 PM
Furnace Venting Question jlaky2000 HVAC 6 10-10-2011 06:24 PM
Horizontal Venting of Wood Furnace ejfitzpatrick HVAC 2 10-17-2009 06:16 PM
venting a high efficiency furnace through the roof (how high) allAboutDIY HVAC 11 10-21-2008 12:48 PM




Top of Page | View New Posts

Copyright © 2003-2014 Escalate Media. All Rights Reserved.