Disconnect the existing battery and using the strap provided pull out of its plastic holder.Fit new battery into strap and push into its holder.Reconnect. Refit and tighten threaded plug after lightly greasing thread and checking sealing 'O' ring is serviceable.Light RunBefore retuning the actuator to the valve connect it to an electricity supply of the correct voltage and check that it is both electrically and mechanically serviceable.Refit actuator to valve or gearbox and fully bolt down.