• 1. Hot Water ON switch
    Switches on the electrical supply to the water heater. When in the ON position the switch is illuminated. With the switch in the ON position the water heater will heat up whenever an “Off-Peak” electrical supply period is available.
  • 2. Hot Water 'Boost' Switch and Indicator
    Switches on the electrical supply to the “Boost” element when pressed. NOTE: the switch does not latch in the “on” position. When the supply to the “Boost” element is switched on the indicator will illuminate. The “boost” is timed to operate for a maximum of one hour, this is sufficient time to fully reheat a smaller “boost” volume of water. The “Boost” element cannot be switched on if the Hot Water “On” switch is in the ‘’off’’ position.
  • 3. Alarm
    This indicator will flash RED when there is a problem with the boiler. If flashing alone there is a water flow problem, if flashing at the same time as the DEMAND/OVERHEAT indicator flashes RED there is an over-heat problem.

    The boiler will not operate until the problem has been rectified and reset. Contact your installer or Heatrae Sadia Service Department if a fault ALARM occurs.
  • 4. Heat
    This indicator will illuminate GREEN as the boiler produces heat. It will show the degree of heat being applied, it will only be fully illuminated when the boiler is on full power output. As the boiler adjusts its power output to the heating demand (modulating) the indicator will alter in intensity.
  • 5. Demand / Overheat
    When illuminated GREEN this indicates that there is a heating demand for the central heating from the Programmable Room Thermostat. It will flash for
    approximately 2 to 3 minutes whilst the boiler undergoes a series of self diagnostic tests. When the indicator glows steady green it indicates that the boiler is heating.

    When flashing RED at the same time as the ALARM indicator it indicates that there has been an over-heat fault on the system.
  • 6. Flow Temp
    This adjuster alters the boiler flow temperature. It will normally have been set to its optimum position during installation. At its minimum position (- fully anticlockwise) the boiler flow temperature is set at 65oC; at its maximum position ( + fully clockwise) the boiler flow temperature is set at 80C.
  • 7. System Pressure
    The Central Heating System Pressure Gauge will indicate the actual water pressure within the central heating system. When the system is cold the pressure should be between 1.0 and 1.5 bar. On switching on the heating a small drop in system pressure may be noted, but the pressure will then rise as the system heats up. When fully hot the system pressure may be up to 2.5 bar.

    If the system pressure drops below 1.0 bar it will require topping up. To do this:
    • Pull the lower front panel forward using the finger holds in the sides of the panel
    • Connect the Filling Loop
    • Open the Filling Loop Isolating Valves and allow system to re-pressurize to between 1.0 and 1.5 bar
    • Close the Isolating Valves
    • Disconnect the Filling Loop and refit lower FRONT PANEL
  • 8.

    Central Heating ON Switch
    Switches on the electrical supply to the boiler to provide central heating. When in the ON position the switch is illuminated. With the switch in the ON position the operation of the boiler will be controlled by the times set on the Programmable Room Thermostat.