Gas hot water storage cylinders
Gas hot water storage systems consist of an insulated cylinder and an integral gas burner. A range of capacities and recovery rates are available, making them capable of meeting requirements of both residential and commercial applications. All units are thermostatically controlled so that reheating at a pre-selected level takes place automatically. Recovery time is rapid.
Gas hot water storage systems are ideal in situations where there are specialist bathroom fittings that demand maximum water pressure, for example, massage shower heads. They are also suitable in situations where there are lengthy pipe runs between draw-off points.
External gas cylinders
External cylinders are an option that saves valuable space inside. They can be easily installed on an outside wall with no need for additional flue materials, as the flue is located on the side of the appliance. The appliance must therefore be located in accordance with NZS5261:2003, Table 16. For more details refer to Ventilation and flueing. External gas cylinders most commonly have fan assisted flues.
Internal gas cylinders
Internal storage cylinders can be recessed into wall cavities, installed in cupboards or fitted in areas like the laundry, basement or roof area. They cannot be installed in a bedroom, bathroom or toilet, and must be sealed from those rooms. Adequate ventilation must be provided.
Internal cylinders most commonly have fan assisted flues and the flue terminal must exit the building in accordance with NZS5261:2003, Table 16. For more details refer to Ventilation and flueing.
As air is required for combustion, the cupboard or space where the internal hot water cylinder is located must have two permanent openings: a lower and upper vent. Both vents need to be to the same area, either indoors or out. If venting is into an internal room, the room must meet minimum room size requirements which can be calculated using this formula:
Appliance Input Rating (MJ/hr) ÷ 3 = minimum m3 room size
Water cylinders cannot be installed on combustible materials unless the manufacturer’s requirements differ. In areas such as the garage where there may be flammable vapours, or if the area might flood, the heater must be lifted off the floor.
Consideration must be given to the size of the cupboard or space to ensure room is left for service access (recommended 610mm clearance from sides and top).