Heater boost switch. For control of electric heating loads. Switches heating load on for a limited time only. Pressing the button selects each time lag choice in turn. The heating then remains on for the chosen time lag before switching off automatically. The button can also be used at any time for selecting a different time lag or for switching off. Heater Boost Switch, for electric heaters Switches on manually, switches off automatically after time lag has elapsed Selectable time lag: 1/4 hour, 1/2 hour 1 hour or 2 hours