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

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
are undamaged. If in doubt fit new 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
plugging the two male spade 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 22. Refit and secure
the immersion heater covers.
(l) Close the drain tap and turn on mains
water supply.
(m) When water flows from the hot taps allow
to flow for a short while to purge air and
flush through any disturbed particles.
(n) Close hot taps 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 flows
freely through the tundish and discharge
pipework.
(c) Release valve cap and check water flow
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 23).
(b) Slowly open the primary system pressure
relief valve (see diagram 16, page 24) by
twisting its cap for a few seconds.
(c) Check water is discharged and that it flows
freely through the tundish and discharge
pipework.
(d) Release valve cap and check water flow
stops and valve re-seats correctly.
(e) Check pressure in system & repressurise if
required.
8.6 Primary System Expansion Vessel Charge
Pressure
(a) Open the primary system pressure relief
valve and allow water to flow until the
system pressure gauge drops to zero.
(b) Remove the top panel (refer to section 4.2,
page 12).
(c) Remove the dust cap from the primary
system expansion vessel (see diagram 21,
page 29).
(d) Check the charge pressure of the vessel
using a tyre pressure gauge. The pressure
(with system de-pressurised) should be
1.0 to 1.2 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
Top Panel
Primary
Expansion
Vessel
Primary Expansion
Vessel Air Valve
(Fitted with dust cap)
Diagram 21 Primary Expansion Vessel Position
Installation & Servicing Instructions
Pump
29