two water heaters/ one flue

Originally Posted By: m bettencourt
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Two water heaters mounted side by side in attic. 3" flues from each heater connect with one roof penetration. I wasn’t there, but should the minimum flue be 5" where they are joined? (100% plus 50%)


Also, I was skimming through "Mastering the Profession 4th edition" and on page 276, ninth paragraph under natural gas-venting, it says that "Two 90 degree elbows are permitted in a vent system......" I thought that G2427.6.4 "Offsets" states that you can't exceed 60 degrees. What is the discrepancy? Thanks.


Originally Posted By: dvalley
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A pic would be fantastic.



David Valley


MAB Member


Massachusetts Certified Home Inspections
http://www.masscertified.com

"Some cause happiness wherever they go; others, whenever they go."

Originally Posted By: m bettencourt
This post was automatically imported from our archived forum.



I wasn’t there, but I am just curious about the requirement for joining two flues together (3" B-vent) from the water heaters. Should they need to be greater than 4 1/2 inches and can they just join in wye of some sort? Also wanted info on the other question I had. Thanks.


Originally Posted By: m bettencourt
This post was automatically imported from our archived forum.



I am looking for some guidance on the difference between sections G2427.6.4 which speaks of gas offsets a 2428.2.3 which seems to cover the same thing but allows two 90s. In my example of two side by side gas water heaters and a common vent, which code would apply?