Servicing - Heatrae Sadia ELECTROMAX Installation & Servicing Instructions Manual

9.3 Servicing

WARNING: DISCONNECT FROM ALL
E L E C T R I C A L S U P P L I E S B E F O R E
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
a. 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 22)
b. Relieve the system pressure by twisting
the red cap located on the Primary
Pressure Relief Valve (see Diagram
16, page 23). Observe the system
pressure indicated on the Primary
System Pressure Gauge located on
the fascia panel of the Electromax.
c. Remove the sealing cap from the
front of the Primary Drain Valve (see
Diagram 20, page 27) and replace it
with the hose connector supplied.
d. 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.
e. Open the Primary Drain Valve and
allow the water to drain from the
Primary circuit.
f. 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
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 27). 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 27) 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.
Installation & Servicing Instructions 37