Cleaning The Storage Vessel; Magnesium Anode(S); Safety Valve - andrews 32/143 Installation Manual, Operation And Service Manual

SECTION 6
CLEANING THE
STORAGE
VESSEL
ALL MODELS
MAGNESIUM
ANODE(S)
ALL MODELS
SAFETY
VALVE
HI-FLO RANGE
RESTART
ALL MODELS
SERVICING
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.
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 5 litres
for Standard Models and 10 litres for Hi-Flo Models, or more dependant 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 anode(s) if fitted and plug off the connections using 3/4" BSP plugs. (Hi-
TM
Flo models only). Re-fit the Correx
Magnesium sacrificial anode(s) is (are) fitted to the top of the storage vessel.
The anode(s) will prevent corrosion of the storage vessel. Anode condition should be
checked annually and replaced if excessive wear is present. We recommend that the
anode(s) are replaced annually
1. Withdraw each anode using a 1
diameter.
2. An anode should be replaced, if, at any point along it's length, the diameter is reduced to
half, or less of original. Particular attention should be paid to the ends.
3. If the anode is encrusted with limescale, it should be either wire brushed to reveal bright
metal or replaced.
Where Correx anodes are fitted, no maintenance is necessary.
TM
Check the condition and operation of the safety valve as described below.
During Servicing
Examine the safety valve for deposits or let-by. Clean or replace as necessary.
When Re-Commissioning
Operate the safety valve, ensuring no let-by when the valve is reset and reseated.
NOTE! For adjustable valves, reduce the rating until the valve operates and gives full flow.
Reset the valve and check for let-by. For lever operation valves, operate lever and check
for let-by when reseated.
Re-light and carry out commissioning checks as detailed in Section 4, Commissioning.
Set the thermostat control to the required user setting.
TM anode(s) when the descaling operation is complete.
1
in AF socket spanner. A new anode measures 21mm
⁄
1 6
42