SERVICING
SECTION 6
CLEANING
THE STORAGE
VESSEL
ALL MODELS
26
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 INFORMATION
When descaling the water storage heater your attention is drawn to the following
guidelines.
SAFETY FIRST
DUE TO THE CORROSIVE NATURE OF THE DESCALING FLUID ITS ESSENTIAL THAT
SUITABLE PROTECTIVE CLOTHING EQUIPMENT IS USED AND ADEQUATE
VENTILATION IS AVAILABLE WHEN DESCALING. IT IS IMPORTANT TO FOLLOW
DESCALING MANUFACTURERS INSTRUCTION BEFORE AND DURING USE.
1.
Isolate the electrical power supply to burner.
2.
Close water inlet valve and drain heater tank.
3.
Remove magnesium sacrificial anode.
Note: It is recommended that a new anode is fitted.
4.
Add suitable hydrochloric based descale acid, the requirement is normally 5 litres for
OFS25 & OFS29 and 10 for OFS63, OFS90, OFS108 & OFS163.
5.
After a minimum of one hour relight the burner for 2 minutes (Maximum).
6.
Turn the burner off 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 hot outlet nipple/anode (OFS25 & OFS29).
10. Replace anodes using service anode (articulated) part no. C333.
11. Relight the burner and allow the heater to come to its working temperature.
IMPORTANT!
Remove Correx anode(s) if fitted. Re-fit the Correx anode(s) when descaling operation is
complete.
