Riello Array AR 399 SE Installation, Operation And Service Manual page 65

APPENDIX
Horizontal venting system (sealed combustion); X≥4" (102
mm)
X
Horizontal concentric system (sealed combustion)
2
1
2
1
Vertical venting system (sealed combustion); X > 12" (305
mm); Y 12" (305 mm) above maximum snow level or at least
24" (610 mm) whichever is great
X
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RECYCLING AND DISPOSAL APPENDIX
1
2