Maintenance; Maintenance Requirements; Check Cylinder Water Supply; Descaling Immersion Heaters - Heatrae Sadia ELECTROMAX Installation & Servicing Instructions Manual

8.0 Maintenance

8.1 Maintenance requirements

To ensure the
performance of the Electromax it should be
regularly maintained. Maintenance should be
carried out by a competent person and any
replacement parts used should be authorized
Heatrae Sadia Electromax spare parts. It is
recommended that maintenance is carried
out annually and should include the checks
detailed in the sections below. The primary
system inhibitor concentration should also be
checked and topped up if necessary.
IMPORTANT: Disconnect
supplies before removing the covers or panels
to the appliance.

8.2 Check cylinder water supply

(a) Turn off the mains water supply to the
Electromax and release the system pressure
by opening a hot tap. Some hot water will
flow for a short while, this is normal.
(b) Unscrew the larger plastic 'nut' on the
reducing valve cartridge (see diagram 17,
page 24). Remove the moulded housing.
(c) Remove the strainer mesh housed inside
the moulding. Wash any particulate matter
from the strainer mesh under clean running
water.
(d) Replace the pressure reducing valve
cartridge in the housing and re-fit to the
brass body of the cold water combination
valve.
(e) Remove the dust cap from the top of the
secondary expansion vessel. Check the
charge pressure of the vessel using a tyre
pressure gauge. The pressure (with system
de-pressurised) should be 3.5 bar. If lower
than the required setting it should be re-
charged using a tyre pump (Schrader valve
type). DO NOT over charge. Re-check the
charge pressure and when correct replace
the dust cap.
28 Installation & Servicing Instructions
continued optimum
ALL electrical

8.3 Descaling immersion heaters

In hard water areas where no water treatment
measures have been taken the immersion
heaters may require descaling. The Electromax
cylinder must be drained before the immersion
heaters can be removed.
(a) Disconnect the electrical supplies to the
Electromax.
(b) Remove the front panels (refer to section
3.2, page 9).
(c) Connect a hose to the DHW drain point
(see diagram 20, page 28) & open hot taps
to releive pressure from system. Unscrew
square head ed stop plug to allow water
to drain from the cylinder. If water fails
to drain from the cylinder vent the unit
by manually opening the temperature/
pressure relief valve.
(d) Remove the immersion heater covers by
unscrewing the securing screws.
(e) Disconnect the wiring from the immersion
heater thermostats.
thermostats by carefully pulling outwards
from the immersion heaters.
(f) 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
Filling Loop
Primary
System
Drain
Filling Loop
Connection
Isolating Valves
Diagram 20 Drain Points
Remove the
Cylinder Drain
Connection