Hayward H-Series Indoor Vent Adapter, Vertical to Roof
This is a Hayward-branded vent adapter for use with Hayward's Universal H-series Low NOx gas heaters. Use it in installations where negative pressure venting is going up through the roof. You can use "B" vent pipe to vent to the roof. It is guaranteed compatible with the H150FDN, H150FDP, H200FDN, H200FDP, H250FDN, H250FDP, H300FDN, H300FDP, H350FDN, H350FDP, H400FDN and H400FDP. It ships with a replacement top (called a flue cover) to your heater with a big round hole through which the vent pipe goes.