WaterFurnace 7 Series - Manual (Page 9)

9
7 SERIES 50Hz 700A11 INSTALLATION MANUAL
Figure 7: Closed Loop Ground Source Application
NOTE: For closed loop systems with antifreeze protection,
set SW2-1 to the “LOOP” (-9.4°C) position. (Refer to the
DIP Switch Settings table in the Aurora Control section.)
Once piping is completed between the unit, pumps and the
ground loop (see figure below), final purging and charging
of the loop is required. A flush cart (or a 1.5 HP pump
minimum) is needed to achieve adequate flow velocity
in the loop to purge air and dirt particles from the loop
itself. Antifreeze solution is used in most areas to prevent
freezing. Flush the system adequately to remove as much
air as possible then pressurize the loop to a static pressure
of 276-345 kPa (summer) or 345-517 kPa (winter). This is
normally adequate for good system operation. Loop static
pressure will fluctuate with the seasons. Pressures will be
higher in the winter months than during the cooling season.
This fluctuation is normal and should be considered when
initially charging the system.
After pressurization, be sure to turn the venting (burping)
screw in the center of the pump two (2) turns open (water
will drip out), wait until all air is purged from the pump,
then tighten the plug. Variable speed pumps do not have
a venting screw. Ensure that the loop pumps provide
adequate flow through the unit(s) by checking the pressure
drop across the heat exchanger and comparing it to the unit
capacity data in this catalog. 0.14-0.19 L/s of flow per ton of
cooling capacity is recommended in earth loop applications.
Flexible Duct
Collar
Vibration Absorbing Pad
P/T Plugs
Drain
Hot Water Generator
Connections
Auxiliary
Heater
Knockout
Low
Voltage to
Thermostat
Unit Supply
Auxiliary Heat
Supply
Insulated piping
or hose kit
Disconnects
(If Applicable)
Unit Power
P/T
TO
LOOP
Geo
Link
®
Flow
Center
GeoLink ®
Polyethylene w/
Armaflex ®
Insulation
NOTE: Additional information can be found in Flow
Center installation manual and Flush Cart manual.
Closed Loop Ground Source Systems
Figure 8: Primary/Secondary Hook-up
7 Series to
Electromechanical Units
7 Series to
Envision Units
7 Series Unit #1
with AXB Board
7 Series Unit #1
with AXB Board
7 Series Unit #1
with AXB Board
7 Series to
5 or 7 Series Units
C S
With pump
wired to
Unit 2
With pump
wired to Unit 1
With pump
wired to
Unit 1
With pump
wired to
Unit 2
Shut
Down
C C
SL1
In
SL1
Out
VS PUMP SLAVE
OUT IN C C 1 2
VS PUMP SLAVE
OUT IN C C 1 2
VS PUMP SLAVE
OUT IN C C 1 2
VS PUMP SLAVE
OUT IN C C 1 2
Multiple Units on One Flow Center
NOTE: This feature is only available in the Aurora Advanced
Control package (AXB board), NOT the Aurora Base
Control (ABC).
When two units are connected to one loop pumping system,
pump control is automatically achieved by connecting the
SL terminals on connector P2 in both units with 2-wire
thermostat wire. These terminals are polarity dependant (see
Figure 8). The loop pump(s) may be powered from either
unit, whichever is more convenient. If either unit calls, the loop
pump(s) will automatically start. The use of two units on one
flow center is generally limited to a total of 1.26 L/s capacity.
Variable Speed Pump Setup
When using a variable speed pump flow center (FCV1-GL,
FCV2-GL, FCV1-GLNP, or FCV2-GLNP) the use of an AID
Tool will be necessary to adjust minimum and maximum
flow rates. The factory default is: minimum=50% and
maximum=100% speed levels. See the 7 Series Variable
Speed Pump Setup and Modulating Water Valve Setup
instructions within the Unit Startup section which is located
in the back of this manual. Always ensure that there is
adequate flow for the heat pump. See Recommended
Minimum/Maximum Flow Rates table.
NOTE: When sharing a flow center, the variable speed heat
pump should be the primary unit. When two variable speed
heat pumps share a flow center, the larger capacity heat
pump should be the primary unit.
Recommended Minimum/Maximum Flow Rates
Model
and Size
Closed Loop Open Loop
Min. Flow Rate Max. Flow Rate Min. Flow Rate Max. Flow Rate
L/s L/s L/s L/s
NVK009 0.3 0.8 0.3 0.5
NVK012 0.3 0.9 0.3 0.6
NVK015 0.3 1.1 0.3 0.8
5/23/13