AO Smith direct vent venting question

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Adkroot

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Installing an AO Smith gdv40 - their non-power vented direct vent water heater- and finding that their tech support seems to not have any knowledge.

The manual allows for two 90’s- one from the vertical off the top of the unit to horizontal, and a second if there’s a need for an off-set exit horizontally out the wall.

I have an installation option that would require a 45 from the vertical off the top of the unit, a second 45 shortly after back to vertical, and then the 90 out the wall.

I would think the two 45’s wouldn’t be an inhibiting factor to the draft and intake as much as the permissible two 90’s and a 80” max horizontal run, but I don’t want to base the installation on my assumption alone. Seems they could’ve answered it.
Any thoughts on this installation?
Thanks
 

Michael Young

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Installing an AO Smith gdv40 - their non-power vented direct vent water heater- and finding that their tech support seems to not have any knowledge.

The manual allows for two 90’s- one from the vertical off the top of the unit to horizontal, and a second if there’s a need for an off-set exit horizontally out the wall.

I have an installation option that would require a 45 from the vertical off the top of the unit, a second 45 shortly after back to vertical, and then the 90 out the wall.

I would think the two 45’s wouldn’t be an inhibiting factor to the draft and intake as much as the permissible two 90’s and a 80” max horizontal run, but I don’t want to base the installation on my assumption alone. Seems they could’ve answered it.
Any thoughts on this installation?
Thanks

Pictures would help.

Make sure you buy the direct-vent water heater with the flexible vent. (6" large vent; 3" smaller vent inside the 6" larger flexible material). If you didn't buy the flex-vent, return it. I will send their hard-vent crap back in a bloody heartbeat; I refuse to fight with their hard-vent poorly manufactured crap. I ONLY install flexible vent style direct-vent heaters.

Note: If you go with the Bradford-white flexible direct-vent heater, their outer vent is 5" diameter. That might save you some chipping or cutting.

Install your vent first. Secure it with the long screws. Make sure the arrows are pointing UP.
on the inside, position your water heater. Pull the vent and center it to where its going to be. Let the vent touch the front-center-ledge of the water heater. Let the flexible vent hang loose against that front ledge of te heater. Take your tin snips and cut the vent 4" shorter than where it touches the front center of the front of the heater. cut both the inner 3" vent and the outer 6" vent. make a clean cut. If your cut is not clean, cut it again. We don't want any of the metal vent folded towards the inside of the vent. we want a nice clean surface because we're going to slide it over the adapter on the heater.

use some of the red high temp silicone and smear it around the adapter built onto the heater. Slide the 3" vent over that adapter and push it all the way down (about a 4" lip) and tighten your band around the vent. You will need a long-handled driver to reach in there. Wear gloves. the 6" vent is going to cut the top of your hands.

Now dry-fit the 6" vent. make sure it goes all the way down around the adapter. The adapter for the 6" is only about a 1" lip. you don't have much to work with here. dry-fit first. if it slides on smoothly, smear some of that high temp silicone and slip the vent in place. While you hold the vent down, have your helper tighten the band. MAKE SURE the vent is sitting all the way down...flush with the back rim of that adapter. The vent likes to ride up. if that happens you crush your vent and now you have to start all over again. so hold the the back part of the vent down flush while your helper tightens. Work slow. STOP and readjust if it starts to crush. Crushing in that 6" is the biggest mistake I see guys make out here.

cool... your venting is done.

Water pipes. personally, I use a 3/4" brass coupling. then I install a 3/4" x 4" brass nipple. Then I install a 3/4" tee. Then I install a 3/4" x 6" brass nipple. Then I install a 3/4' brass elbow. Then I screw my expansion tank onto the elbow. Note: if you don't use the coupling and the 4" nipple, you won't be able to install the tee because the vent is in your way.

I use 18" slink lines on the hot and cold sides. I install a new full port ball valve on the cold side., preferably located where it's easy to reach. I adapt to pex right off the wall.

cool... your water line is done

hook up your bas line and you're done. If it's hard piped and you're not experienced with gas, go buy one of those flexible yellow gas connectors and make your life easier.

check your house. make sure you have CARBON MONOXIDE DETECTORS. if you don't buy a few and follow the instructions (about $25/each).

Call you local municipality and get a homeowners permit. Have the job inspected. It won't cost much. And since you're not familiar, this will give you the additional layer of safety. if you live in a cold climate, you will need to wrap thick walled insulation to protect your water pipe and you will need to protect the expansion tank from freezing. your new heater already has sealed combustion. It doesn't have to be on a stand. So set it on the ground. Make sure you have a wheel stop or a bollard to protect the heater from getting slammed by your car (if its in the garage).

I think that about covers it
 

Jeff H Young

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the instruction manualin regard to bends number number of degrees etc is your requirements not what someone tells you over the phone you might get clarity from them but if what you are doing isnt in line with the manual then you might get written up . So its your opinion and interpetation and your inspectors interpetation he might not know a darn thing or care in which case your safety belongs to you.
 
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