Heatrae Sadia ELECTROMAX SOLAR Installation & Servicing Instructions Manual page 51

6.4 IMMERSION HEATERS
1. Connect a hose to the domestic hot water drain point and unscrew square headed stop
plug to drain the cylinder. If water fails to drain from the cylinder, vent the unit by manually
opening the temperature and pressure relief valve.
2. Ensure all electrical supplies are isolated.
3. Remove the immersion heater covers by unscrewing the securing screws.
4. Disconnect the wiring from the immersion heater thermostats. Remove the thermostats
by carefully pulling outwards from the immersion heaters.
5. Unscrew immersion heater backnuts using the key spanner supplied with the unit. Remove
the immersion heaters. Over time the immersion heater gaskets may become stuck to the
mating surface, to break the seal insert a round bladed screwdriver into one of the pockets
on the immersion heater and gently lever up and down.
6. Carefully remove any scale from the surface of the immersion heater elements. DO NOT
use a sharp implement as damage to the element surface could be caused. Ensure sealing
surfaces are clean and seals are undamaged. If in doubt fit new sealing gaskets.
7. Replace the immersion heaters ensuring the right angled element is inserted into the lower
immersion heater boss and hangs vertically downwards towards the base of the unit.
8. Secure the immersion heaters in place using the backnuts previously removed. It may be
helpful to support the immersion heater using a round bladed screwdriver inserted into
one of the thermostat pockets whilst the backnut is tightened.
9. Replace the thermostats by carefully plugging the two male spade terminations on the
underside of the thermostat head into the corresponding terminations on the element.
10. Rewire the immersion heaters in accordance with figure 19, page 32. Refit and secure
the immersion heater covers.
11. Close the drain tap and turn on mains water supply.
12. When water flows from the hot tap allow to flow for a short while to purge air and flush
through any disturbed particles.
13. Close hot tap and then open successive hot taps to purge any air.
FIGURE 35: IMMERSION HEATER REMOVAL
IMMERSION
HEATER
COVER
COVER
SECURING
SCREW
GASKETS
THERMOSTAT
BACKNUTS
UPPER
IMMERSION
HEATER
LOWER
IMMERSION
HEATER
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