Maintenance - Heatrae Sadia UTC 15 Installation And User Instructions Manual

5.9 Setting the "mid-range" position:
Rotate the thermosatat knob to the mid postion. Remove the termi-
nal cover by using a large flat bladed screwdriver to depress the
three snap lugs located in the three top rectangular depressions.
Holding the thermostat knob in position turn the terminal cover
over and remove the backing disc from the underside of the cover.
Turn the backing disc over and refit to the knob ensuring the notch
locates with the boss on the underside of the cover. Refit the
terminal cover, the thermostat will now be locked in the "mid-
range" position.
5.10 Setting the "hot" position:
Rotate the thermostat knob to mid way through the hot graduated
range (red graphic). Follow the procedure detailed above, however
in this case the knob should be held in the "hot" position previously
set. When the terminal cover has been refitted the thermostat will be
locked in the "hot" position.

6.0 MAINTENANCE

Little maintenance is required, however in hard water areas the unit will
require periodic descaling to ensure efficient operation. To descale the
unit:
6.1 Switch off and disconnect the electrical supply. Turn off the water
supply to the unit.
6.2 Open a hot tap to relieve any system pressure. Disconnect the
plumbing connections to the unit and remove from the wall bracket
(note full weights of units). Empty unit through the outlet connec-
tion.
6.3 Remove the terminal cover by using a large flat bladed screwdriver
to depress the 3 snap lugs located in the top 3 rectangular depres-
sions.
6.4 Remove the plastic disc from the thermostat spindle. Remove the
insulating pad from the terminal housing. Disconnect the electrical
terminations to the thermostat. Disconnect earth links to the
earthing stud.
6.5 Remove the element plate assembly by unscrewing the five securing
screws, tapped jacking points are provided. 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.
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