SERVICING
SECTION 6
FLUEWAY
MAGNESIUM
ANODE
17
The burner should be checked annually. The flueway and baffle should be checked if
sooting occurs and if necessary cleaned as follows:-
1. Depress slightly the gas control knob and turn to "OFF". Remove outer burner cover
and inner cover. Remove the fixing screws to remove the inner cover.
2. Disconnect burner gas tube, pilot tube and thermocouple at gas control.
3. Remove burner assembly complete with pipes and thermocouple lead.
4. Remove flue assembly and flue box on heater to reveal flue baffle.
5. Inspect and clean the secondary flue installation as necessary.
6. Lift out the baffle from inside the central flueway.
7. Clean the flueway with a brush and clean any deposit from the underside of the
storage vessel bottom and from the flue baffle.
8. Re-assemble in the reverse order.
IT IS IMPORTANT THAT THE BURNER IS CORRECTLY LOCATED IN THE BURNER
SUPPORT BRACKET ON BASE OF COMBUSTION CHAMBER. DO NOT OVERTIGHTEN
THE THERMOCOUPLE CONNECTION.
Screw in hand tight and tighten an extra 1/4 turn with a spanner.
9. Re-light and carry out commissioning check as above.
IMPORTANT
A magnesium sacrificial anode is fitted into the top of he water storage vessel.
The function of the anode is to provide additional corrosion protection for the inside of the
vessel. The condition of the anode should be checked, at least annually, during servicing.
The original diameter of the anode is 22mm (7/8"), If at any point along its length, the
anode is eroded to half, or less, of the original diameter it should be replaced with new.
Particular attention should be paid to the extreme ends. The anode/hot outlet nipple can
be unscrewed from the top of the heater (see page 18). If the anode is encrusted with
limescale it should be either cleaned by wire brushing to reveal bright metal or replaced.
Where correx anodes are fitted no anode maintenance is required.
CLEANING THE STORAGE VESSEL
Scale formation in the base area of the storage vessel which may occur in hard water
areas. It is usually associated with high usage and high water temperatures. It is
characterised by a rumbling noise (kettling) when the burner is lit and should be rectified
by chemical descaling.
DESCALING
When descaling the water storage heater your attention is drawn to the following
guidelines.
SAFETY FIRST
DUE TO THE CORROSIVE NATURE OF THE DESCALE FLUID IT ITS ESSENTIAL THAT
SUITABLE PROTECTIVE CLOTHING EQUIPMENT IS USED AND ADEQUATE VENTILATION
IS AVAILABLE WHEN DESCALING.
1. Turn gas control on water heater to ‘OFF’ position and isolate the gas supply.
2. Close water inlet valve and drain heater tank.
3. Remove magnesium sacrificial anode (s).
Note: It is recommended that a new anode(s) is fitted.
4. Add suitable hydrochloric based descale acid, the requirement is normally 5 litres for
standard range 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 off descale fluid through drain port.
7. Open cold water feed valve and fill heater tank.
8. Drain and flush out heater for minimum of 30 minutes.
9. Replace anodes.
10.Replace gas supply and re-light heater.
