Servicing - Heatrae Sadia ELECTROMAX Installation & Servicing Instructions Manual

9.3 Servicing

WARNING: DISCONNECT
ELECTRICAL SUPPLIES BEFORE BEGINNING
ANY WORK ON THE UNIT. THE WATER
CONTAINED IN EITHER THE WATER HEATER
CYLINDER OR THE PRIMARY HEATING
CIRCUIT MAY BE VERY HOT – CARE MUST
BE TAKEN TO AVOID SCALDING.
To remove any water carrying parts the system
must first be drained. The water heater cylinder
and primary circuit are not connected so must
be drained separately. It is not necessary to
drain the system for all servicing actions, those
that require draining are indicated.
9.3.1 Draining the Electromax Primary
Circuit
To avoid draining the complete primary
radiator or underfloor circuit the Electromax
primary circuit can be isolated by shutting off
the primary circuit isolating valves fitted on the
primary flow and return pipes (see diagram 15,
page 23)
(a) Relieve the system pressure by twisting the
red cap located on the primary pressure
relief valve (see diagram 16, page 24).
Observe the system pressure indicated on
the primary system pressure gauge located
on the fascia panel of the Electromax.
(b) Remove the sealing cap from the front
of the primary drain valve (see diagram
20, page 28) and replace it with the hose
connector supplied.
(c) Attach a hose to the hose connector and
secure in place with a hose clip. Place the
discharge point of the hose at a point
below the level of the Electromax where
the water drained will safely drain away.
(d) Open the primary drain valve and allow
the water to drain from the Primary circuit.
(e) Water carrying parts attached to the
Electromax primary circuit can now be
removed. However, take care when
removing parts as some residual water
may still be contained and this may be
very hot.
9.3.2 Draining the Electromax Water Heater
Cylinder
FROM ALL
(a) Turn off the mains water supply to the
unit.
(b) Open a hot tap supplied by the Electromax
to relieve the system pressure. Caution:
some hot water will flow from the tap!
(c) Attach a hose to the hose connection
on the drain point of the filling loop (see
diagram 20, page 28). Place the discharge
point of the hose at a point below the level
of the Electromax where the water drained
will safely drain away.
(d) Open the square headed drain screw (see
diagram 20, page 28) and allow the unit to
drain.
9.3.3 Removing the Automatic Air Vent (see
diagram 40, page 38)
(a) Drain primary circuit.
(b) The automatic air vent is located on the
pump body. It can be removed either with
the pump fitted or removed.
(c) Unscrew the pump extension and remove
assembly from pump body.
(d) Unscrew the automatic air vent from the
pump extension.
(e) Replacement is a reversal of the above
procedure. Ensure that the 'O' ring seals
are correctly located before replacement.
9.3.4 Removing the Primary circulating
pump (see diagram 40, page 38)
(a) Drain primary circuit.
(b) Unscrew top of pump electrical housing
and remove by pulling upwards.
(c) Unscrew pump cable securing gland.
Disconnect
terminals by pressing the spring loaded
clips. Remove pump cable.
(d) Unscrew the union nuts from each end
of the pump body and slide back along
pipework.
(e) The pump can now be lifted from the
unit.
Installation & Servicing Instructions
pump connections from
37