Author Topic: New High Efficiency Furnace Vents  (Read 2782 times)

Offline lymer

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New High Efficiency Furnace Vents
« on: November 13, 2015, 04:14:14 PM »
When they installed my High Efficiency Furnace they removed my 20 year old Mid-Efficiency.  It was exhausted out through the roof by way of old style galvanizing ducting.  They installed the PVC fresh air in and the new PVC exhaust out through my wall.  However I just noticed that the old galvanized ducting that was the exhaust to the roof is still attached to what looks like the hot air phelum.  Or the major ducting where the hot air of the furnace is blown through the ducting to the whole house.  Why is this old chimney style ducting I had on my old furnace even still attached.

In my mind it serves no more purpose

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Re: New High Efficiency Furnace Vents
« Reply #1 on: November 13, 2015, 05:13:04 PM »
Any chance you can post a pic?  The only thing that should be connected to the supply duct are supply vents.  I wonder if maybe this is a outdoor air supply connected to the return duct?

Offline lymer

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Re: New High Efficiency Furnace Vents
« Reply #2 on: November 13, 2015, 07:19:13 PM »
I have always had trouble trying to get pictures up on a forum.  Search help but couldnot find instruction that easily.  Any quick hints

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Re: New High Efficiency Furnace Vents
« Reply #3 on: November 14, 2015, 01:35:52 AM »
Look at the screenshot I posted.  Once you're in a reply window click Additional Options then click Choose File.

Offline lymer

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Re: New High Efficiency Furnace Vents
« Reply #4 on: November 14, 2015, 08:03:14 AM »
I understand the process you have described to attach pictures but any time I try and then click post the screen just goes blank white and puts me in a major wait mode.  Ultimately nothing happens.  The dimensions of my jpeg are 5184 X 3888 and I believe too big to be posted on forums, blogs and other social media sites.  I have never really been sure how to shrink them for these types of sites so that I can post them and I think this is more my personal issue.

However my email is

steve.lynas@gmail.com

and I can attach you the pictures that way if you like

Thanks

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Re: New High Efficiency Furnace Vents
« Reply #5 on: November 14, 2015, 02:33:46 PM »
I attached your pics with some notes.

First those are heat runs supplying the second floor.  I can see the tee where the furnace used to connect to.  It should be capped now and looks like it is.

Does the chimney have 1" clearance from the drywall behind it?

The electrical wiring is installed against Code and cannot touch metal duct.  It should also be properly secured and not installed under the joists.

The water shut off is usually installed on the cold side of the water heater, but they bonded the side without the shut off.  The bonding clamp must be on the cold side and the bonding wire must be kept as short as possible.  It should be attached to the gas pipe dropping to the water heater gas valve.

Offline lymer

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Re: New High Efficiency Furnace Vents
« Reply #6 on: November 14, 2015, 05:11:41 PM »
Thanks again for putting up with this Newb and his lack of forum skills.

I like your pictures.  They explain things very effectively.  So now I feel quite stupid as they are of coarse heat runs to the second floor that makes complete sense.

Chimney duct is 2" from drywall and the angle of the picture I think just makes it look tighter then that

The electrical wire tie wrapped to the duct is "My Bad".   I did that as it was kind of just hanging down where my head would bang into it when I went back there to change Air filters, etc.  I will look into a structural alternative.

The grounding bond to the copper hot water out pipe on my water heater, rather then the cold is an error made by my contractor, I guess.  Is this standard code no matter what geographical location? AND What is the rational for it? 

As you can see from pic it has been cut to that exact length so the question is how would one extend it if they wanted to set up to code.  Do they have to start from the beginning or could they splice a section in?

Thanks Again

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Re: New High Efficiency Furnace Vents
« Reply #7 on: November 14, 2015, 06:59:14 PM »
You could just take some insulation and put it between the wire and duct.

The bonding is designed to protect the gas piping from things like lightening strikes.  No matter where you live it should attach to the cold side as that leads back to the main water meter which is also bonded.  You should be able to remove the clamp and install it on the cold side, but first remove the other clamp and attach it to the gas pipe on the water heater.  You would probably have excess bond wire that you could cut off, once you move the clamp closer to the water heater.  The clamp can be installed on the cold cooper water line and connect to any steel gas pipe.  I have no idea why they would waste bond wire when they could have used only 1' or so to the water heater gas piping.

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Re: New High Efficiency Furnace Vents
« Reply #8 on: November 16, 2015, 07:30:13 PM »
Also how much distance is there from the metal water heater vent to the underside of the white plastic furnace vents?

You need 6" clearance.  If you have less that 6" clearance you could have a problem.  They should have used Bvent, which only needs 1" clearance, then adapted back to Cvent.