Installation manual

10
ENVISION RESIDENTIAL INSTALLATION MANUAL
Figure 7: Closed Loop Ground Source Application
NOTE: For closed loop systems with antifreeze protection, set SW2-2 to the “loop.” position (Refer to the DIP Switch
Settings table in the Microprocessor 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 40-50 PSI (summer)
or 50-75 PSI (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. 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 the specification catalog. 2.5 to 3 GPM of flow per ton of cooling capacity is recommended in earth loop applications.
Multiple Units on One Flow Center
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 20
GPM capacity.
Envision to
Electromechanical Units
Shut
Down
CC
SL1
In
SL1
Out
Envision Unit #1
To Electromechanical Unit
C
S
Shut
Down
CC
Shut
Down
CC
SL1
In
SL1
Out
SL1
In
SL1
Out
Single Speed
Envision Unit #1
With pump
wired to Unit 1
With pump
wired to
Unit 2
Envision to Envision
Microprocessor Units
Envision Unit #2
Single Speed
With pump
wired to Unit 1
With pump
wired to
Unit 2
Shut
Down
CC
Shut
Down
CC
SL1
In
SL1
Out
SL1
In
SL1
Out
Dual Capacity
Envision Unit #1
Envision Unit #2
Dual Capacity
Envision to Envision
Microprocessor Units
Figure 8: Primary/Secondary Hook-up
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
GeoLink
®
Flow
Center
GeoLink
®
Polyethylene w/
Armaflex
®
Insulation
NOTE: Additional information can be found
in Flow Center installation manual (IM1961)
and Flush Cart manual (WFS302).
Closed Loop Ground Source Systems