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6.13 Cleaning the Storage Vessel
6.14 Descaling
6.15 Restart
51
The storage vessel should be checked and cleaned
annually.
Scale formation in the base of the vessel may occur, particularly
in hard water areas, and is normally associated with high usage
and high water temperatures. It is characterised by a rumbling
noise when the main burner is lit. Scale formation in the base of
the vessel will affect the efficiency of the water heater and
reduce the life of the storage vessel.
It should be noted that the failure of the storage vessel due to
scale formation on the base will not be covered by the terms of
the warranty.
Any scale formation which cannot be removed by normal means
of cleaning should be removed by chemical descaling. See
below.
When descaling the heater, attention is drawn to the following
guidelines:
CAUTION
DUE TO THE CORROSIVE NATURE OF DESCALING
FLUID, IT IS ESSENTIAL THAT SUITABLE
PROTECTIVE CLOTHING IS USED AND ADEQUATE
VENTILATION AVAILABLE.
1. Turn gas control to OFF and isolate gas supply.
2. Close water inlet valve and drain heater tank.
3. Remove magnesium anode(s). It is recommended that new
anode(s) is (are) fitted.
4. Add suitable hydrochloric acid based descale fluid. The
requirement is normally 10 litres or more dependent on the
amount of limescale present.
5. After a minimum of one hour, restore gas supply and turn on
main gas burner for 2 minutes maximum.
6. Isolate gas supply and drain descale fluid through drain port.
7. Open cold water feed valve and fill heater tank.
8. Drain and flush out heater for 20 minutes minimum.
9. Replace anode(s)
10. Restore gas supply and re-light heater.
Note
IMPORTANT- Remove Correx Powered Anodes if fitted
and plug off the connections using ¾" BSP plugs.Re-fit
the Correx Powered Anodes when the descaling
operation is complete.
Re-light and carry out commissioning checks as detailed in
Section 4, Commissioning. Set the thermostat control to the
required user setting.
Servicing
6
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