Manually reset the thermostat if the main burner fails to light. If this happens the control will go into lockout and the valve will immediately turn off automatically. Turn off the "ON/OFF" switch for a minimum of five seconds to reset the unit. Do not attempt more than two ignitions in succession. Allow at least five minutes for the gas to clear before attempting to ignite the heater again.
Check the venting system. Ensure there are no obstructions to the flow of combustion and ventilation air. Remove obstructions as needed.
Inspect the main burner and pilot burner flame. A blue flame is ideal. Clean the burners if the flame is yellow. Keep the burner area free of combustible materials and flammable liquids.
Keep the thermostat setting to 78 degrees or lower to conserve energy. The American Red Cross considers this to be a healthy temperature for swimming. Once you have set the thermostat at the desired temperature, tighten the thermostat stopper. Set the thermostat to 65 degrees if the pool is only used occasionally.
Adjust the pressure switch on the heater if the unit is below the water level of the pool or spa. The pressure switch keeps the circuit open when the pump is not on and operating. When the pump is engaged, the pressure switch closes the circuit and the heater turns on. Backwash the filter and clean out the pump lint basket before adjusting the pressure switch. Turn on the circulation pump. Switch on the heater and push the thermostat to its highest setting. Turn the adjustment knob clockwise until the heater shuts down. Turn the adjustment knob counterclockwise 1.25 turns to re-fire the heater. Switch the pump off and the heater should shut down. Repeat the process if it does not. Switch the pump on and off several times to assure proper adjustment.