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11
Typical open loop piping is shown below. Always maintain
water pressure in the heat exchanger by placing water control
valves at the outlet of the unit to prevent mineral precipitation.
Use a closed, bladder-type expansion tank to minimize mineral
formation due to air exposure. Ensure proper water flow through
the unit by checking pressure drop across the heat exchanger
and comparing it to the figures in unit capacity data tables in the
specification catalog. 1.5-2 gpm of flow per ton of cooling capacity
is recommended in open loop applications.
Discharge water from the unit is not contaminated in any manner
and can be disposed of in various ways, depending on local codes,
i.e. recharge well, storm sewer, drain field, adjacent stream or
pond, etc. Most local codes forbid the use of sanitary sewer for
disposal. Consult your local building and zoning departments to
assure compliance in your area.
NOTE:
For open loop/groundwater systems or systems that do not
contain an antifreeze solution, set SW2-Switch #1 to the “WELL”
(30°F) position. (Refer to the DIP Switch Settings table in the
Aurora Control section.) Slow opening/closing solenoid valves
(type V100FPT) are recommended to eliminate water hammer.
Figure 10: Open System - Groundwater Application
Open Loop Ground Water Systems
Flexible
Duct Collar
Vibration
Absorbing Pad
P/T Plugs
Drain
Desuperheater
Connections
Auxiliary
Heater
Knockout
Low Voltage
to Thermostat
and Valve
Unit Supply
Aux. Heat Supply
Water Out
Water In
Shut Off Valves
Boiler Drains
For HX Flushing
Disconnects
(IfApplicable)
Rubber Bladder
Expansion Tank
Solenoid
Valve
Shut Off Valves
(to isolate solenoid
valve while acid flushing)
Strainer
Flow Control
Valve
(on outlet of
Solenoid Valve)
Compressor
Line Voltage
Figure 9c: Open Loop Solenoid Valve Connection Option
Typical quick operating external 24V water solenoid valve
(type PPV100 or BPV100) wiring.
NOTE:
SW2-4 and SW2-5 should be “OFF” to cycle with the compressor.
Acc Com
Acc NC
Acc NO
1
2
3
C
R
P1
P2
SV
Solenoid
Valve
ABC Board
NOTE:
SW2-4 should be “ON” and SW2-5 should be “OFF” when using a slow
opening (V100FPT) water valve.
Figure 9a: Modulating Water Valve Connection Option
Typical 0-10VDC modulating water valve. Unit must have AXB Board
VS PUMP
GND
24 VAC
0-10DC
1
2
3
R
C
ABC BOARD
AXB BOARD
2 1
VALVE
Figure 9b: Open Loop Solenoid Valve Connection Option
Typical slow operating external 24V water solenoid valve
(type V) wiring.
C
R
Acc Com
ACC NC
Acc NO
C
W/Y
V Valve
ABC Board
AFFINITY & AFFINITY ADVANCED SINGLE & DUAL CAPACITY SERIES INSTALLATION MANUAL