8
General
Water-to-water heat pumps may be successfully applied
in a wide range of residential and light commercial
applications. It is the responsibility of the system designer
and installing contractor to ensure that acceptable water
quality is present and that all applicable codes have been
met in these installations. Failure to adhere to the guidelines
in the water quality table could result in loss of warranty.
Application
These heat pumps are not intended for direct coupling to
swimming pools and spas. If used for this type of applica-
tion, a secondary heat exchanger must be used. Failure to
supply a secondary heat exchanger for this application will
result in warranty exclusion for primary heat exchanger cor-
rosion or failure.
Water Treatment
Do not use untreated or improperly treated water.
Equipment damage may occur. The use of improperly
treated or untreated water in this equipment may result in
scaling, erosion, corrosion, algae or slime. The services of a
qualified water treatment specialist should be engaged to
determine what treatment, if any, is required. The product
warranty specifically excludes liability for corrosion,
erosion or deterioration of equipment.
Material Copper 90/10 Cupronickel 316 Stainless Steel
pH Acidity/Alkalinity 7 - 9 7 - 9 7 - 9
Scaling Calcium and
Magnesium Carbonate
(Total Hardness)
less than 350 ppm
(Total Hardness)
less than 350 ppm
(Total Hardness)
less than 350 ppm
Corrosion
Hydrogen Sulfide Less than 0.5 ppm (rotten egg
smell appears at 0.5 ppm) 10 - 50 ppm Less than 1 ppm
Sulfates Less than 125 ppm Less than 125 ppm Less than 200 ppm
Chlorine Less than 0.5 ppm Less than 0.5 ppm Less than 0.5 ppm
Chlorides Less than 20 ppm Less than 125 ppm Less than 300 ppm
Carbon Dioxide Less than 50 ppm 10 - 50 ppm 10 - 50 ppm
Ammonia Less than 2 ppm Less than 2 ppm Less than 20 ppm
Ammonia Chloride Less than 0.5 ppm Less than 0.5 ppm Less than 0.5 ppm
Ammonia Nitrate Less than 0.5 ppm Less than 0.5 ppm Less than 0.5 ppm
Ammonia Hydroxide Less than 0.5 ppm Less than 0.5 ppm Less than 0.5 ppm
Ammonia Sulfate Less than 0.5 ppm Less than 0.5 ppm Less than 0.5 ppm
Total Dissolved Solids (TDS) Less than 1000 ppm 1000 - 1500 ppm 1000 - 1500 ppm
LSI Index +0.5 to -0.5 +0.5 to -0.5 +0.5 to -0.5
Iron Fouling
(Biological Growth)
Iron, FE2+ (Ferrous)
Bacterial Iron Potential < 0.2 ppm < 0.2 ppm < 0.2 ppm
Iron Oxide Less than 1 ppm, above this
level deposition will occur
Less than 1 ppm, above this
level deposition will occur
Less than 1 ppm, above this
level deposition will occur
Erosion
Suspended Solids Less than 10 ppm and filtered
for max. of 600 micron size
Less than 10 ppm and filtered
for max. of 600 micron size
Less than 10 ppm and filtered
for max. of 600 micron size
Threshold Velocity
(Fresh Water) < 6 ft/sec < 6 ft/sec < 6 ft/sec
NOTES: Grains = ppm divided by 17
mg/L is equivalent to ppm
2/22/12
The heat exchangers and water lines in the units are copper
or cupronickel tube. There may be other materials in the
building’s piping system that the designer may need to take
into consideration when deciding the parameters of the
water quality.
If an antifreeze or water treatment solution is to be used,
the designer should confirm it does not have a detrimental
effect on the materials in the system.
Contaminated Water
In applications where the water quality cannot be held to
prescribed limits, the use of a secondary or intermediate
heat exchanger is recommended to separate the unit from
the contaminated water.
The following table outlines the water quality guidelines
for unit heat exchangers. If these conditions are exceeded,
a secondary heat exchanger is required. Failure to supply
a secondary heat exchanger where needed will result in a
warranty exclusion for primary heat exchanger corrosion
or failure.
WARNING: Must have intermediate heat
exchanger when used in pool and spa
applications.
Water Quality Guidelines
Water Quality
RH SERIES ENGINEERING GUIDE
