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Figure 13: Typical Open Loop/Well Application
Ground-Water Heat Pump Applications
valve or water control valve on the discharge line. Measure the
pressure drop through the unit heat exchanger, and determine
fl ow rate from tables 9a through 9c. Since the pressure is
constantly varying, two pressure gauges may be needed.
Adjust the valve until the desired fl ow of 1.5 to 2 gpm per ton
[2.0 to 2.6 l/m per kW] is achieved. A second method of fl ow
control requires a fl ow control device mounted on the outlet of
the water control valve. The device is typically a brass fi tting
with an orifi ce of rubber or plastic material that is designed
to allow a specifi ed fl ow rate. On occasion, fl ow control
devices may produce velocity noise that can be reduced by
applying some back pressure from the ball valve located on
the discharge line. Slightly closing the valve will spread the
pressure drop over both devices, lessening the velocity noise.
NOTE: When EWT is below 50°F [10°C], a minimum of 2
gpm per ton (2.6 l/m per kW) is required.
Water Coil Low Temperature Limit Setting
For all open loop systems the 30°F [-1.1°C] FP1 setting
(factory setting-water) should be used to avoid freeze
damage to the unit. See “Low Water Temperature Cutout
Selection” in this manual for details on the low limit setting.
CAUTION!
CAUTION!
Refrigerant pressure activated water regulating
valves should never be used with this equipment.
