Water Quality - Rinnai HJ Cooper Owner's Manual

Water quality

HJ Cooper by Rinnai water heaters are manufactured to suit most
NZ council water supplies. However some water supplies can have
a detrimental effect on the water heater, its operation, and life
expectancy.
Pitting corrosion
The HJ Cooper by Rinnai stainless steel tanks are made from 2101 grade duplex stainless steel.
This material has very good resistance to pitting corrosion with a Pitting Resistance Equivalent
Number (PREN) of 26. This is a commonly used engineering indicator of corrosion resistance in
stainless steel materials. The higher the PREN number the greater the resistance. In comparison
304 grade stainless, which is commonly used in domestic cookware and kitchen sinks, has a
PREN number of 19. This means that HJ Cooper by Rinnai stainless steel tanks are highly resistant
to pitting corrosion, but not completely immune from it.
Pitting corrosion may occur in the form of deposit attack if the water supply has a high
percentage of dissolved solids present. It is advised in areas with a high concentration of
dissolved solids in the water supply that consultation with water quality and filtration experts be
undertaken.
Hard water
Hard water (containing calcium carbonate) can cause scaling on hot surfaces. We recommend
a water temperature of no more than 65 °C to minimise scale build-up. Scale reducing or water
softening devices should be considered in hard water areas. The unit is not guaranteed against
damage due to scaling.
Water quality outside the limits (as set down below) will void this warranty. Water quality tests must be
carried out at the customer's own cost but Rinnai will reimburse any reasonable test costs where water
quality is within the limits tabled.
Water Quality and Impurity Limits
TDS (Total Dissolved Solids)
Up to 600 mg/L or ppm
Most metropolitan water supplies fall within these limits. If you are unsure about water quality, please
contact Rinnai and we will provide you with the details of an authorised agency able to test your water
for compliance to Rinnai standards. If sludge or foreign matter is present in the water supply, a suitable
filter should be incorporated in the water supply.
Some examples of water quality issues where water may need to be treated:
• Hard water (areas including Wanganui)
• Aggressive water (areas including Christchurch)
• Both hard and aggressive water (some bore water)
12 | Mains pressure indoor stainless steel cylinders: Owner and installer guide: 20132-D 04-15
Total Hardness CaCO Dissolved (free) CO
3
Up to 200 mg/L or ppm Up to 25 mg/L or ppm 6.5-8.5 Between -1.0-0.8
pH Langelier Index
3