12
6.1.11 Re-commission the unit following the INSTALLATION and
COMMISSIONING instructions.
The Pressure (expansion) Relief Valve should be regularly
checked. This is to remove limescale deposits and to verify that it is
not blocked. To check the valve:
6.1.12 Manually operate the valve by twisting the cap. Ensure water
flows freely from the valve and through the discharge pipes.
Ensure the valve re-seats correctly when released.
The Expansion Vessel, if fitted, should have a pre-charge
pressure of 0.41 MPa (4.1 bar). This can reduce over time and
eventually require re-charging. To do this:
6.1.13 Turn off water supply to the unit; open a hot tap to relieve system
pressure.
6.1.14 Remove dust cap from top of Expansion Vessel
6.1.15 Check pre-charge pressure using a tyre pressure gauge. If the
pressure is lower than 0.41 MPa (4.1 bar) it should be recharged
using a tyre pump (Schraeder Valve type). DO NOT OVER
CHARGE.
6.1.16 Re-check pressure and when correct replace dust cap.
6.1.17 Turn on mains water supply and close hot tap.
EARTH POINT FIXING
FIGURE 06: CORRECT ORIENTATION OF ELEMENT PLATE
(VIEWED FROM TOP WITH COVER REMOVED)
COLD WATER INLET
(BLUE)
HOT WATER OUTLET
(RED)
