Replacing a Power Vent w/ Direct Vent

[KFreerksen]

My power vent AO Smith 40 gallon gas water heater has been going out. The tank is pretty rusty underneath so I was planning on replacing it. However, I can get a tankless for the same or cheaper than another power vented, and I’d rather not spend that much right now unless I have to. Currently, the power vent is horizontally vented out an exterior wall right by the air intake and vent for my furnace. Can I use the same opening in the wall for the direct vent? Can it be that close to the furnace vent? I can’t find anything about the direct vent requirements other than I have to do it out of metal pipe with an incline.

 

[GReynolds929]

My power vent AO Smith 40 gallon gas water heater has been going out. The tank is pretty rusty underneath so I was planning on replacing it. However, I can get a tankless for the same or cheaper than another power vented, and I’d rather not spend that much right now unless I have to. Currently, the power vent is horizontally vented out an exterior wall right by the air intake and vent for my furnace. Can I use the same opening in the wall for the direct vent? Can it be that close to the furnace vent? I can’t find anything about the direct vent requirements other than I have to do it out of metal pipe with an incline.

did you mean atmospheric vent? Most direct vents I've installed cost as much or more than a power vent. Direct vent water heaters also have the exhaust piped through the intake pipe concentrically, and are usually pretty short runs.

 

[frodo]

 

[KFreerksen]

did you mean atmospheric vent? Most direct vents I've installed cost as much or more than a power vent. Direct vent water heaters also have the exhaust piped through the intake pipe concentrically, and are usually pretty short runs.
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View attachment 24235

yes, I was wrong before. I meant atmospheric

 

[Mitchell-DIY-Guy]

You asked a simple question, and you didn't get a simple answer. Here it is: NO.

You cannot substitute a conventional atmospheric vent water heater for a power vent model. You cannot remove the power vent PVC venting pipe and replace with metal, and exhaust it out the same place. You cannot take a working power vent blower assembly, mount it on top of an atmospheric vent model to turn it into a power vent model.

If you have a power vent model, replace with same. End of story...

NOW depending on your house, there is a possibility that there was or is a vent assembly in place for an atmospheric vent water heater. It would probably be obvious, or probably go into the base of a chimney. Short of that, replace with same.

 

[breplum]

I highly recommend a power vented condensing tankless.
Navien NPE series: 60' horizontal in 2" PVC. Which requires support every 4"
Slight gravity back towards the heater, but there are requirements for termination, but you may be able to create a new opening if the old hole is unsuitable.

 

[Pat the Plumber CIL]

Put a power vent back in like you have . Only advantage to a direct vent is noise . You would have to find a new location for that to work and that will push cost up . I have only installed one direct vent water heater and I would not want one in my house .

 

[frodo]

My power vent AO Smith 40 gallon gas water heater has been going out. The tank is pretty rusty underneath so I was planning on replacing it. However, I can get a tankless for the same or cheaper than another power vented, and I’d rather not spend that much right now unless I have to. Currently, the power vent is horizontally vented out an exterior wall right by the air intake and vent for my furnace. Can I use the same opening in the wall for the direct vent? Can it be that close to the furnace vent? I can’t find anything about the direct vent requirements other than I have to do it out of metal pipe with an incline.

LEGALLY
You can replace the Existing water heater with the SAME water heater and you will not run into a code problem. "you are grandfathered in"
IF..You change to a different type of water heater THEN, You WILL bring the new water heater up to CURRANT codes.

You stated that the vent for your heater is next to the intake for the heating unit.
IF you installed anything but what you currently have. The vent would be required to be 10" from that intake.

 

[Mitchell-DIY-Guy]

...highly recommend a power vented condensing tankless....

Remember the OP didn’t really want to spend the money on a power vent or tankless unless necessary. A condensing tankless is even more money!! Probably not the most sense to consider if one is on a budget. Remember there’s probably an upgrade to the gas line and potential reconfigured water lines, driving up the cost further.