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 11-30-2010, 04:27 PM   #1
Newbie
 
Join Date: Nov 2010
Posts: 4
Share |
Default

Gas furnace venting Qs (non high eff)


Hello all!

I was hoping someone could help me with a couple of questions about gas furnace venting. I have a gas furnace in the attic with a short run (3' maybe) of metal venting to the roof.

The current venting is in bad shape so I need to redo it. It has 4" double-walled aluminum, a single walled bend (!) and then double-walled to the roof vent outside.

There is no sealing anywhere - pieces are just dry fitted together.

Q1) do I need to seal the venting to the flue collar (?) on the furnace or is it OK to dry fit.

Q2) do I need to seal each segment of venting?

Q3) My understanding is that the double-walled venting needs to be 1" from anything combustible. What's the best way to ensure that this requirement is met - particularly at the roof?

Thank you!!

WallyWoggle is offline   Reply With Quote
Old 11-30-2010, 04:47 PM   #2
Member
 
Join Date: Oct 2009
Location: Nebraska
Posts: 2,362
Default

Gas furnace venting Qs (non high eff)


Double wall locks together with a slight turn of the pipe so no sealing required. Should be a screw in each joint and 3 screws to hold it on the flue collar. To get clearance it's best with 2 people. One in the attic watching the clearance and the other setting the pipe pumb and level. The roof person will trim wood as needed.

Marty S. is offline   Reply With Quote
The Following User Says Thank You to Marty S. For This Useful Post:
WallyWoggle (11-30-2010)
Old 11-30-2010, 05:25 PM   #3
Newbie
 
Join Date: Nov 2010
Posts: 4
Default

Gas furnace venting Qs (non high eff)


Quote:
Originally Posted by Marty S. View Post
Double wall locks together with a slight turn of the pipe so no sealing required. Should be a screw in each joint and 3 screws to hold it on the flue collar. To get clearance it's best with 2 people. One in the attic watching the clearance and the other setting the pipe pumb and level. The roof person will trim wood as needed.
Thanks Marty. I see now how the double wall pipes lock together.

I attached a pic of the flue collar... it's basically just a hard plastic piece with no screw holes. The outer part of the double-walled vent pipe slides over it and the inner part "catches" on it. Is this a good enough seal?

thx
Attached Thumbnails
Gas furnace venting Qs (non high eff)-img_4789.jpg  
WallyWoggle is offline   Reply With Quote
Old 11-30-2010, 05:53 PM   #4
Member
 
Join Date: Oct 2009
Location: Nebraska
Posts: 2,362
Default

Gas furnace venting Qs (non high eff)


The inner liner should also go over that. If not a short piece(less then 5" long) of single wall can be used as a starter. Use self tapping screws on the collar or predrill, they break easy.
Marty S. is offline   Reply With Quote
The Following User Says Thank You to Marty S. For This Useful Post:
WallyWoggle (11-30-2010)
Old 11-30-2010, 06:22 PM   #5
Newbie
 
Join Date: Nov 2010
Posts: 1
Default

Gas furnace venting Qs (non high eff)


They make metal connectors to replace the plastic one.
kelipop is offline   Reply With Quote
The Following User Says Thank You to kelipop For This Useful Post:
WallyWoggle (11-30-2010)
Old 12-09-2010, 11:36 AM   #6
Newbie
 
Join Date: Nov 2010
Posts: 4
Default

Gas furnace venting Qs (non high eff)


The saga continues...

Thanks to the advice of folks here and a lot of Googling I was able to put together a decent vent pipe. I had to build a pipe from the furnace to the old chimney and cap which was a bit tricky.

Once everything was in place I noticed that the roof penetration for the chimney has roofing paper and shingles that were not particularly well trimmed... they are crowding into the 1" gap around the pipe. Is this something I should be concerned about? Any recommendations out there on how/what tool to use to trim it up if needed?
WallyWoggle is offline   Reply With Quote
Old 12-09-2010, 06:41 PM   #7
Member
 
Join Date: Oct 2009
Location: Nebraska
Posts: 2,362
Default

Gas furnace venting Qs (non high eff)


Use a knife and cut away. Us HVAC guys will get denied on inspection if there's not the correct clearance. Roofers on the other hand don't get inspections here and I've seen a lot of flues touching wood after a reroof and the places didn't burn down.

Marty S. is offline   Reply With Quote
The Following User Says Thank You to Marty S. For This Useful Post:
WallyWoggle (12-09-2010)
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
HVAC!! Furnace venting issues!!!!! HELP! Hurricane_Ditka HVAC 14 09-08-2010 01:58 PM
Venting med. efficiency furnace and H2O heater thru wall? cbrc5eric Building & Construction 2 04-02-2010 11:07 PM
Loud, low toned hum from high efficiency furnace. Ryan C HVAC 5 10-16-2009 05:38 AM
bryant plus 90 high eff. furnace kenny w HVAC 1 02-09-2009 05:45 PM
High pitched sound from furnace michaeljc70 HVAC 5 12-19-2008 08:53 AM




Top of Page | View New Posts

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