York YAWS018 - 075, Installation Manual, Page: 9 / 52

9
Field Connected Water Piping cont.
Earth Coupled Systems with Flow Center
Once piping is completed between the unit, flow center
and the earth loop, final purging and charging of the loop
is needed. A flush cart (at least a 1.5 HP or 1.12 kW pump)
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. Maintain
the pH in the 7.6-8.2 range for final charging.
Flush the system adequately to remove as much air as
possible. Then, pressurize the loop to a static pressure of
50-75 psi [345-517 kPa]. This is normally adequate for good
system operation. Ensure that the flow center provides
adequate flow through the unit by checking pressure drop
across the heat exchanger and by comparing it to the
figures shown in the Pressure Drop tables. Usually, 3 GPM/
ton [0.054 L/s/kW] L/s/kW or minimum 2.25 GPM/ton
[0.04 L/s/kW] of cooling capacity is needed in closed loop
earth-coupled applications
Typical Closed Loop Earth Coupled Installation
Line Voltage
Disconnect
Load Liquid
Connections
Vibration Absorbing
Mesh or Air Pad
P/T Plugs
Unit Connector Kits
with Insulation
Earth Coupled Loop
Piping with Insulation
Figure 8b: Primary/Secondary Hook-up
5 Series to
Electromechanical Units
To Electromechanical Unit
5 Series to
Envision Units
Envision Unit #2
5 Series Unit #1
with AXB Board
5 Series Unit #1
with AXB Board
5 Series Unit #1
with AXB Board
5 Series Unit #2
with AXB Board
5 Series to
5 Series Units
C S
VS SLO SLI
OUT IN C C
VS SLO SLI
OUT IN C C
With pump
wired to
Unit 2
With pump
wired to Unit 1
VS SLO SLI
OUT IN C C
Shut
Down
C C
SL1
In
SL1
Out
With pump
wired to
Unit 1
With pump
wired to
Unit 2
VS SLO SLI
OUT IN C C
Figure 8a: Primary/Secondary Wiring with Aurora Base
Control (no AXB Board)
CC
T2 T1
Compressor
C
R
S Blue
L1 L2
Black
Red
Tan(6)
Cap
Ext Pump
1/2 hp Total
208-230/60/1
Pump
G
1
2
PB1
1
2
Pump
Circuit
Breaker
Circuit
Breaker
1
5A
5A
Optional Internal
HWG Pump
HWG
Pump
Purple
Hot Water
Limit Switch
130°F
Blue
1
2
3
Cabinet
HW Switch
Field Supplied
Relay for Heat
Pump 1
Field Supplied
Relay for Heat
Pump 2
Heat Pump 1
Contactor Coil
Heat Pump 2
Contactor Coil
Field Supplied
Fuses 5A
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 8b). 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 20 gpm capacity.
NOTE: To achieve this same feature when heat pumps have
only the Aurora Base Control, follow Figure 8a. Installer will
be required to supply fuses, two relays, and wiring.
AFFINITY SINGLE STAGE HYDRONIC INSTALLATION MANUAL