HTP SSU-119SE - Manual (Page 17)

17
LP-199 REV. 4.15.14
heater and marked Hot and Cold. It is recommended that unions or flexible copper connectors be used so heater can be easily
serviced. Install a shut-off valve on the cold feed near the solar water heater to isolate the tank for future service.
Provide clear access to the storage tank, pump, expansion tank, mixing valve, time clock and other key components. The components
on the potable side of the system may require future service or maintenance, so it is recommended that the connections be made with
brass unions. You must use copper and brass fittings in plumbing the solar storage tank and expansion tank. The use of galvanized
fittings, nipples, dielectric unions, CPVC, PVC, or other plastic pipe is prohibited.
Hard copper connections to the city cold water supply line and home hot water feed lines are recommended.
The gaskets in standard water heater flex hose connectors can become brittle and compressed over time and begin leaking on the
water heater. If not detected in a timely manner, a drip or leak may cause serious damage to the tank’s electrical components, or, in
extreme cases, cause the tank to leak from the outside in.
B. WATER CHEMISTRY REQUIREMENTS
Chemical imbalance of the water supply may affect efficiency and cause severe damage to the water heater and associated equipment.
HTP 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 water heater due to lime scale build-up, 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 and may shorten the service life of the water
heater. Failure of the water heater 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 water heater. Operating temperatures above 135
o
F will further accelerate the build-
up of lime scale and may shorten the service life of the water heater.
Water that is classified as hard and very hard must be softened to avoid water heater failure.
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 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 tank 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
water heater 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).