14
6.0 MAINTENANCE
WARNING: DISCONNECT FROM ALL ELECTRICAL SUPPLIES BEFORE
BEGINNING ANY WORK ON THE B3M OR C3M WATER HEATER. FLUID
CONTAINED IN THE WATER HEATER MAY BE VERY HOT!
To ensure the continued safe and efficient operation of the unit, it should be
regularly maintained.
Maintenance should be carried out by a competent person and any
replacement parts used should be authorised Heatrae Sadia spare parts.
It is recommended that maintenance carried out annually and should include
the checks detailed in the section below.
Little maintenance is required, however in hard water areas the unit will require
periodic descaling to ensure efficient operation. To descale the unit:
1. Switch off and disconnect the electrical supply. Turn off the water supply
to the unit.
2. Open a hot tap to relieve any system pressure. Empty unit by opening
the drain cock in the inlet pipework.
3. Remove the terminal cover by using a large flat bladed screwdriver to
depress the 4 snap lugs located in the 4 rectangular depressions on the
bottom cover.
4. Disconnect the electrical terminations to the element. Disconnect earth
links to the earthing stud. Withdraw the thermostat and thermal cut-out
capillary tubes from the pocket on the element plate.
5. Remove the element plate assembly by unscrewing the five securing
screws, tapped jacking holes are provided (NOTE: a quantity of water
may still be present in the container, it is recommended that a container
be placed under the unit to collect any spillage). Remove any loose scale
from the container. Carefully clean off any scale from the element and
thermostat pocket. DO NOT clean scale from interior container walls.
6. Re-assemble the element plate assembly fitting a new sealing gasket.
Rewire the unit with reference to the Wiring Diagrams.
7. Re-commission the unit following the INSTALLATION and
COMMISSIONING instructions.
