Closed Loop Ground Source Systems - WaterFurnace AT022C/D Installation And Maintenance Manual

Figure 6 - Closed Loop—Cooler/Boiler System
Electric heat
assembly
(optional)
Flexible Duct
Collar
Insulate supply
plenum and use at
least a 90° elbow
to reduce noise
Closed Loop
Ground
Source
Systems
6
PREMIER 2 SINGLE-SPEED INSTALLATION AND MAINTENANCE MANUAL
3/8"
Threaded rods (6)
Disconnects
Line Voltage
Hanging
Brackets
(included)
The proper water flow must be assured to each unit whenever the unit operates. To assure
proper flow, use pressure/temperature ports to determine the flow rate. These ports should be
located adjacent to the supply and return connections on the unit. The proper flow rate cannot be
accurately set without measuring the water pressure drop through the refrigerant-to-water heat
exchanger (circuit setters may also be used). See Table 2 on page 22 for water flow and
pressure drop information.
NOTE: For boiler/cooling tower systems with no antifreeze solution, set SW2-2 to the
"WELL" position.
GROUND SOURCE SYSTEMS
NOTE: For closed loop systems with antifreeze protection, set SW2-2 to the "LOOP"
position.
Once piping is completed between the unit, flow center and the ground loop (see Figure 7
on page 7), final purging and charging of the loop is required. A WaterFurnace 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 50-75 psi (winter) or 40-50 psi (summer). 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.
To Thermostat
To Line
Power
P/T Plugs
Hose Kits
Cooler/Boiler Loop