10
ENVISION RESIDENTIAL INSTALLATION MANUAL
Open Loop Ground Water Systems
Typical open loop piping is shown below. Always maintain water pressure in the heat exchanger by placing water control
valves at the outlet of the unit to prevent mineral precipitation. Use a closed, bladder-type expansion tank to minimize
mineralformationduetoairexposure.Insureproperwaterowthroughtheunitbycheckingpressuredropacrosstheheat
exchangerandcomparingittotheguresinunitcapacitydatatablesinthespecicationcatalog.1.5-2GPMofowperton
of cooling capacity is recommended in open loop applications.
Discharge water from the unit is not contaminated in any manner and can be disposed of in various ways, depending
onlocalcodes,i.e.rechargewell,stormsewer,draineld,adjacentstreamorpond,etc.Mostlocalcodesforbidtheuseof
sanitary sewer for disposal. Consult your local building and zoning departments to assure compliance in your area.
Note:Foropenloop/groundwatersystemsorsystemsthatdonotcontainanantifreezesolution,setSW2-Switch#2tothe
“WELL”position.(Refertothetableonpage28.)Slowopening/closingsolenoidvalves(typeVM)arerecommendedtoeliminate
water hammer.
Figure 9b: Open Loop Solenoid Valve Connection Option
Typical slow operating external 24V water solenoid valve
(type VM) wiring.
Figure 9a: Open Loop Solenoid Valve Connection Option
Typical quick operating external 24V water solenoid valve
(type PPV100 or BPV100) wiring.
Flexible
Duct Collar
Vibration
Absorbing Pad
P/T Plugs
Drain
Desuperheater
Connections
Auxiliary
Heater
Knockout
Low Voltage
to Thermostat
and Valve
Unit Supply
Aux. Heat Supply
Water Out
Water In
Shut Off Valves
Boiler Drains
For HX Flushing
Disconnects
(IfApplicable)
Rubber Bladder
Expansion Tank
Solenoid
Valve
Shut Off Valves
(to isolate solenoid
valve while acid flushing)
Strainer
Flow Control
Valve
(on outlet of
Solenoid Valve)
Compressor
Line Voltage
Figure 10: Open System - Groundwater Application
Note:
SW2-3 should be in the Comp “ON” position.