Installation Manual

13
WHL-019 REV. 12.17.14
H. WATER CHEMISTRY
Chemical imbalance of the water supply may affect efficiency and cause severe damage to the water heater and associated equipment.
Westinghouse recommends having water quality professionally analyzed to determine whether it is necessary to install a water
softener. It is important that the water chemistry on both the domestic hot water and central heating sides are checked before installing
the water heater, as water quality will affect the reliability of the system. Failure of a heat exchanger due to lime scale build-up on the
heating surface, low pH, or other chemical imbalance IS NOT covered by the warranty.
Operating temperatures above 135
o
F will further accelerate the build-up of lime scale on the heating surface and may shorten the
service life of the water heater. Failure of a heat exchanger due to lime scale build-up on the heating surface, low pH, or other chemical
imbalance IS NOT covered by the warranty.
Outlined below are water quality parameters which need to be met in order for the system to operate efficiently for many years.
Water Hardness
Water hardness is mainly due to the presence of calcium and magnesium salts dissolved in water. The concentration of these salts is
expressed in mg/L, ppm, or grains per gallon as a measure of relative water hardness. Grains per gallon is the common reference
measurement used in the U.S. water heater industry. Hardness expressed as mg/L or ppm may be divided by 17.1 to convert to grains
per gallon. Water may be classified as very soft, slightly hard, moderately hard, or hard based on its hardness number. The minerals in
the water precipitate out as the water is heated and cause accelerated lime scale accumulation on a heat transfer surface. This lime
scale build-up may result in premature failure of the heat exchanger. Operating temperatures above 135
o
F will further accelerate the
build-up of lime scale on the heating surface and may shorten the service life of the water heater.
Water that is classified as hard and very hard must be softened to avoid heat exchanger failure. See below for further information about
water hardness.
CLASSIFICATION
MG/L OR PPM
GRAINS/GAL
Soft
0 – 17.1
0 - 1
Slightly Hard
17.1 – 60
1 – 3.5
Moderately Hard
60 – 120
3.5 – 7.0
Hard
120 – 180
7.0 – 10.5
Very Hard
180 and over
10.5 and over
If the hardness of the water exceeds the maximum level of 7 grains per gallon, water should be softened to a hardness level no lower
than 5 grains per gallon. Water softened as low as 0 to 1 grain per gallon may be under-saturated with respect to calcium carbonate,
resulting in water that is aggressive and corrosive.
pH of Water
pH is a measure of relative acidity, neutrality or alkalinity. Dissolved minerals and gases affect water pH. The pH scale ranges from 0 to
14. Water with a pH of 7.0 is considered neutral. Water with a pH lower than 7 is considered acidic. Water pH higher than 7 is
considered alkaline. A neutral pH (around 7) is desirable for most potable water applications. Corrosion damage and heater failures
resulting from water pH levels of lower than 6 or higher than 8 ARE NOT covered by the warranty. The ideal pH range for water
used in a storage tank or a water heater system is 7.2 to 7.8.
Total Dissolved Solids
Total Dissolved Solids (TDS) is a measurement of all minerals and solids dissolved in a water sample. The concentration of total
dissolved solids is usually expressed in parts per million (ppm).
Water with a high TDS concentration will greatly accelerate lime and scale formation in the hot water system. Most high TDS
concentrations precipitate out of the water when heated. This can generate a scale accumulation on the heat transfer surface that will
greatly reduce the service life of a water heater. This scale accumulation can also impede the ability of the heat exchanger to transfer
heat into the water. A heat exchanger damaged or blocked by lime/scale accumulation must be replaced.
The manufacturer of the water heater has no control of water quality, especially TDS levels in your system. Total dissolved solids in
excess of 2,000 ppm will accelerate lime and scale formation in the heat exchanger. Heat exchanger failure due to total dissolved solids
in excess of 2,000 ppm is a non-warrantable condition. Failure of a water heater due to lime scale build up on the heating surface
IS NOT covered by the warranty.
Hardness: 7 grains
Chloride levels: 100 ppm
pH levels: 6-8
TDS: 2000 ppm
Sodium: 20 mGL