Envision Peripherals Geothermal Indoor Split Heat Pumps Closed Loop Ground Source Systems

P/T Plugs

Vibration Absorbing Pad or Air Pad

Rubber Hose Connector Kit CK4L or CK4S

DHW Out

DHW In

Flow Center

Electrical Supply

Lineset

To Air

Handler

Disconnect

Insulated

GeoLink

Flow Center

Thermostat Wire From Air Handler

To Loop

Figure 7: Typical Split System Application Closed Loop - Earth Coupled

ENVISION SERIES INSTALLATION MANUAL

Closed Loop Ground Source Systems

Note: For closed loop systems with antifreeze protection, set SW2-2 to the “loop” position (see table on page 21).

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 remove the plug in the end of the loop pump motor(s) (if applicable) to allow trapped air to be discharged and to ensure that the motor housing has been flooded. 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 cata- log. Usually 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.

Figure 8: Primary/Secondary Hook-up

Envision to Envision	Envision to Envision	Envision to
Microprocessor Units	Microprocessor Units	Electromechanical Units

Dual Capacity Envision Unit #1

Shut	C	C	SL1	SL1
Down			In	Out
With pump
wired to Unit 1
With pump
wired to
Unit 2
Shut	C	C	SL1	SL1
Down			In	Out

Envision Unit #2 Dual Capacity

Single Speed

Envision Unit #1

Shut	C	C	SL1	SL1
Down			In	Out

With pump wired to Unit 1

With pump wired to Unit 2

Shut	C	C	SL1	SL1
Down			In	Out

Envision Unit #2

Single Speed

Envision Unit #1

Shut	C	C	SL1	SL1
Down			In	Out

C S

To Electromechanical Unit

12