Combined Temperature And Pressure Relief Valve; Cleaning The Storage Vessel; Restart - andrews CSC39 Installation Manual, Operation & Service Manual

SECTION 6
COMBINED
TEMPERATURE
AND PRESSURE
RELIEF VALVE
CLEANING THE
STORAGE
VESSEL

RESTART

30
SERVICING
Check the condition and operation of this component at least once a year to ensure
it is free from limescale deposits.
Lift the lever at the top of the valve several times until the valve seats properly without
leakage and operates freely.
Clean or replace as necessary.
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 TM anodes if fitted and plug off the connections using 3/4" BSP plugs.
Re-fit the Correx TM 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.