Suburban Nautilus Water Heater Vent for 50mm to 76mm WallVent to suit Suburban Nautilus Instant Hot Water Heaters. A vent is required for all installations and is available in 3 lengths to suit different wall thicknesses. This vent suits wall thicknesses from 5cm to 7. 6cm (2 3inch). For new installations this vent can be installed directly through the vehicles wall. If replacing an existing Suburban or Atwood tank unit a replacement door panel is also required.