Hayward H150FDN All models English - Page 16

SECTION 3. INSTALLATION Installation above pool/spa surface: If heater is installed less than three (3) feet above the surface of the pool/spa water, install eyeball fittings or directional flow fittings on the end of the return water line to the pool/spa to create adequate back pressure at the heater to operate the pressure safety switch when filter pump is running. If heater is installed more than three (3) feet above surface of pool/spa water, install a loop as shown on Figure 27 to prevent drainage of water in heater during filter change. For installation below pool/spa surface, refer to Section 4. HIGHER THAN TOP OF HEATER If used, a chlorinator must be installed down stream from the heater in the pool return line and at a lower elevation than the heater outlet connection. See Figure 28. Install a separate positive seal, corrosion resistant check valve (EXAMPLE: Rainbow Plastics #17288 or #172323) between the heater outlet and chlorinator to prevent highly concentrated sanitizers from back-siphoning into the heater. Back-siphoning usually occurs when the pump is shut off and a pressure-suction differential is created. Pressure relief valve: It may be necessary to install a pressure relief valve to conform with local building codes. A 3/4" pressure relief valve with a discharge capacity greater than or equal to the BTUH input of the heater and a pressure relief rating less than the heater working pressure is recommended (see rating plate). WATER LEVEL HEATER PRESSURE RELIEF VALVE FRONT HEADER DISCHARGE CONNECTION Figure 27: Heater Installation Above Pool Automatic chlorinators and chemical feeders: TOP VIEW PUMP HEATER CHLORINATOR FROM POOL FILTER CHECK VALVE CHECK VALVE RETURN TO POOL SIDEVIEW OPTIONAL (PREFERRED) CHLORINATOR HOOKUP FROM POOL CHLORINATOR RETURN TO POOL PUMP FILTER HEATER CHECK VALVE Figure 28: Automatic Chlorinator 14 PLUMBING CONNECTIONS Figure 29: Pressure Relief Valve A 3/4" NPT connection is provided in the front header for installation of a pressure relief valve. See Figure 29. The valve shall be installed directly to the header in a vertical position. To avoid scalding or water damage due to relief valve operation, connect a drain pipe to the valve outlet and run the line to a safe place of discharge. The drain pipe must be at least the same size as the valve discharge connection throughout its entire length and must pitch downward from the valve. No shutoff valve or restriction shall be installed between the relief valve and the discharge of the drainline. The valve lever should be lifted at least once a year to ensure that the waterway is clear.