Using tables from the National Fuel Gas Code or our Sizing & Application Guide, determine the diameter of venting required. The Sizing & Application Guide also offers tips on good design including multi-appliance system sizing and design.
Four-inch oval vent (when installed in 2x4 stud wall with recessed heater) requires clearances as determined by use of 4OBPWS hold-down plate, 4OCP ceiling plate spacers, and 4OFS firestop spacers.
|4" oval pipe||•||•||•||•||•||•||•|
|5" oval pipe||-||-||•||•||•||•||•|
|Model||Size||Dim. A||Dim. B|
|4OP__*||4"||7 1/16||2 7/8|
|5OP__*||5"||10 3/4||2 7/8|
* Add length to complete Model Number.
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