Installation guide

MAINTENANCE / SERVICE SECTION 6

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 efficency 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.

Descaling

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 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.

IMPORTANT

Remove Correx

anodes if fitted and plug off the connections using 3/4” BSP plugs.

Re-fit the Correx

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.

CLEANING

THE

STORAGE

VESSEL

RESTART