Operation Of Cylinder Safety Valves; Operation Of Primary System Safety Valve; Primary System Expansion Vessel Charge Pressure - Heatrae Sadia ElectroMax Installation & Servicing Instructions Manual

e. Disconnect the wiring from the
immersion heater thermostats.
Remove the 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
heater and gently lever up and down.
g. 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
sealing gaskets.
h. 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.
i. 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.
j. Replace the thermostats by carefully
p l u g g i n g t h e t w o m a l e s p a d e
terminations on the underside of the
thermostat head into the corresponding
terminations on the element.
k. Rewire the immersion heaters in
accordance with Diagram 14, page 21.
covers.
l. Close the drain tap and turn on mains
water supply.
28 Installation & Servicing Instructions
particles.
n. Close hot tap and then open successive
hot taps to purge any air.

8.4 Operation of cylinder safety valves

a. Slowly open the Temperature and
Pressure Relief Valve by twisting its
cap for a few seconds.
b. Check water is discharged and that it
discharge pipework.
stops and valve re-seats correctly.
d. Repeat the procedure above for the
Expansion Valve located on the Cold
Water Combination Valve.
8.5 Operation of Primary System Safety
Valve
a. Close the primary flow and return
isolating valves (see Diagram 15, page
22).
b. Slowly open the Primary System
Pressure relief valve (see Diagram 16,
page 23) by twisting its cap for a few
seconds.
c. Check water is discharged and that it
discharge pipework.
stops and valve re-seats correctly.
8.6 Primary System Expansion Vessel
Charge Pressure
a. Open the Primary System Pressure
until the system pressure gauge drops
to zero.
b. Remove the top panel (refer to section
4.2).
c. Remove the dust cap from the Primary
System Expansion Vessel (see
Diagram 21).