How do you wire a timer to a pool heater gas valve?

To wire a timer to a pool heater gas valve, first ensure the power is turned off for safety. Connect the timer's power input to the main power supply and the output to the gas valve's control circuit, following the manufacturer's wiring diagram. Ensure that the timer is rated for the voltage and amperage of the heater. Finally, double-check all connections before restoring power and testing the system.