Concentric vent kit install

[47WDXPW]

I went with a concentric vent kit for a Sterling GG 45,000 Btu natural gas heater. With the instructions it seems the only repeated dimension is to keep the flue length a minimum of 5' (this is a horizontal install) and of course the clearances for outside of the building. My question is can the two ducts (4") coming from the heater to the concentric box be shorter than the two foot pieces that is supplied with the kit, ideally I would like to cut them in half to 2 one foot pieces, would doing this effect the heater operation ?

 

[Dakota46]

I don't remember any requirements of minimum pipe length before the concentric box. Just the minimum 5' effective total length for the exhaust side.

I ran the adapter and a 45 into the concentric box and a 3' straight piece to get the minimum 5'(at least pretty close). Somewhere in the manual there is a reference chart with the callouts for how much a 90 degree elbow or a 45 degree elbow adds for effective length.

Here's how mine looks from the inside.



And from the outside..



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[47WDXPW]

Thanks Dakota46, I'm thinking you haven't had any pressure shut down problems from your install ? Your install looks great!

 

[Dakota46]

I haven't had any shut down issues.

I have probably ran it a couple times 5 or 6 hours continuously. Also ran it a few times to knock the chill off.

No insulation or ceiling in the garage yet so it isn't very effective yet.

I have checked the exhaust venting and the concentric box temperature with one of those laser temperature tools. The concentric box stays around 70-80 degrees and the exhaust vent(piping) surface runs surprisingly cool.

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[thammel]

I installed such a kit from Reznor for my 60k BTU udas. Couple issues to be aware of: 1) the stainless steel z-vent piping is not cheap, 2) Don't use the appliance adaptor (the piece that attaches to the exhaust of the unit) that has a backflow door inside it. I bought one and the unit kept turning off too soon. Apparently the delta pressure sensor in the udas did not like the pressure the flap/door offered. I bought another adaptor without the backflow door and all is fine.

Tom

 

[smalltown]

Dakota just a quick question. Is the exit hole you made in the side of you garage the same as if it was a standard non concentric exhaust? Just wondering for people who think about converting from a non concentric exhaust in the future.

 

[Dakota46]

Dakota just a quick question. Is the exit hole you made in the side of you garage the same as if it was a standard non concentric exhaust? Just wondering for people who think about converting from a non concentric exhaust in the future.

The only difference in the hole exiting the wall was the outer diameter of the pipe. The concentric used a 7" pipe.

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[Radiantec Guy]

Preaction, I'm pretty sure that most of the concentric vent kits I've seen allow for shortening but not lengthening. The best thing to do though, just to be safe, is contact the manufacturer of the vent kit or heater.

 

[47WDXPW]

Preaction, I'm pretty sure that most of the concentric vent kits I've seen allow for shortening but not lengthening. The best thing to do though, just to be safe, is contact the manufacturer of the vent kit or heater.

I did contact the manufacter first, and as expected they would like to see the kit installed unmodified. I thought I would ask here to touch base with people who have installed one where the kit may have needed mods for installation.