Hayward H350FDN/P Universal H-Series Vertical Vent Adapter VENT MODEL:UHXNEGVT13508 It will prevent you from

It will prevent you from walking around dangerous roof edges

the valve will rotate allowing heat collection

Hayward Item Code: SMX306000016

automatically test its own chemistry

Hayward H350FDN/P Universal H-Series Vertical Vent Adapter VENT MODEL:UHXNEGVT13508 It will prevent you fromProduct Description Hayward Universal Forced Draft Negative Vertical Vent Kit Adapter for H350FDN and H350FDP. Hayward Item Code: UHXNEGVT13508 (Adapter Only) This vent kit has been discontinued Features Genuine Hayward Vent Adapter. This vent adapter kit is to be used under negative pressure which is thru roof vertically. Hayward heaters require 1 square inch per 1,000 BTU of fresh air and combustion air supply. Please respect set backs on each side