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lochinvar venting question

but I don't think I've ever seen anything using a 6" in photos or anywhere. The biggest I've done is a KBN399 which used 4". If my cummins diesel can breath through four inch pipe, surely the lochinvar can?


  • pat_3
    pat_3 Member Posts: 89
    lochinvar venting question

    when installing the knight 500 using the concentric vent kit cvk3007,the "y "concentric fitting is 6inch .can a 6x4 bushing be used to reduce the combustion air side or should it remain full 6inch for a specific distance before reducing to 4inch which is at the boiler? i cant find the answer in the install manual...not sure why the "y" supplied wouldn't be a 6x4.thank you in advance for any responses
  • Hvacman
    Hvacman Member Posts: 159
    IOM says:

    Both combustion air and vent are run in 4", reduce at the concentric kit per the IOM page 18.

    Found here: http://www.lochinvar.com/Resources.asp?res=IO&cat=B&prd=KBX
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