WaterFurnace Envision (XL) - Manual (Page 11)

ENVISION 7-25 TONS INSTALLATION MANUAL
12
Water Connections
All supply and return water connections are female pipe thread of size specified in physical dimensions. Never use flexible
hoses smaller than separate water connections on the unit and limit hose length to 10 ft. per connection. Check carefully for
water leaks.
Interior Piping
All units are recommended to be connected to supply and return piping in a two-pipe reverse return configuration. A
reverse return system is inherently self-balancing and requires only trim balancing when multiple quantities of units with
different flow and pressure drop characteristics are connected to the same loop. A direct return system may also be made
to work acceptably, but proper water flow balance is more difficult to achieve and maintain.
Supply and return runouts are usually connected to the unit by short lengths of high pressure flexible hose which are sound
attenuators for both unit operating noise and hydraulic pumping noise. One end of the hose should have a swivel fitting to
facilitate removal for service. Hard piping can also be connected directly to the unit although it is not recommended since
no vibration or noise attenuation can be accomplished. The hard piping must have unions to facilitate unit removal (see
figure 1 & 6) for typical application).
Some flexible hose threaded fittings are supplied with sealant compound. If not, apply Teflon tape to assure a tight seal.
Supply and return shutoff valves are required at each unit. The return shutoff valve can be used for balancing and should be
adjusted for proper flow required, or a manual or automatic flow control device should be on the leaving water hose assembly.
No unit should be connected to the supply and return piping until the water system has been cleaned and flushed
completely. After the cleaning and flushing has taken place, the initial connection should have all valves wide open in
preparation for water system filling.
Water Quality Guidelines
In ground water situations where scaling could be heavy or where biological growth such as iron bacteria will be present,
a closed loop system is recommended. The heat exchanger coils in ground water systems may, over a period of time, lose
heat exchange capabilities due to a buildup of mineral deposits inside. These can be cleaned, but only by a qualified service
mechanic, as special solutions and pumping equipment are required. Hot water generator coils can likewise become scaled
and possibly plugged. In areas with extremely hard water, the owner should be informed that the heat exchanger may
require occasional flushing.
Units with cupronickel heat exchangers are recommended for open loop applications due to the increased resistance to
build-up and corrosion, along with reduced wear caused by acid cleaning.
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, FE 2 + (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
Water Quality