4
Open Loop Well Water Systems
IMPORTANT
: Table 2 must be consulted for water quality
requirements when using open loop systems. A water sample must
be obtained and tested, with the results compared to the table.
Scaling potential should be assessed using the pH/Calcium
hardness method. If the pH is <7.5 and the calcium hardness is
<100 ppm, the potential for scaling is low. For numbers out of the
range listed, a monitoring plan must be implemented due to
probable scaling.
Other potential issues such as iron fouling, corrosion, erosion and
clogging must be considered. Careful attention to water conditions
must be exercised when considering a well water application.
Failure to perform water testing and/or applying a geothermal heat
pump to a water supply that does not fall within the accepted
quality parameters will be considered a mis--application of the unit
and resulting heat exchanger failures will not be covered under
warranty. Where a geothermal system will be used with adverse
water conditions, a suitable plate--frame heat exchanger MUST be
used to isolate the well water from the geothermal unit.
Proper testing is required to assure the well water quality is suitable
for use with water source equipment.
In conditions anticipating moderate scale formation or in brackish
water, a cupronickel heat exchanger is recommended. Copper is
adequate for ground water that is not high in mineral content.
In well water applications, water pressure must always be
maintained in the heat exchanger. This is accomplished by
installing the water solenoid valve in the leaving / outlet water line.
When using a single water well to supply both domestic water and
the heat pump, care must be taken to insure that the well can
provide sufficient flow for both.
In well water applications, a slow closing solenoid valve must be
used to prevent water hammer (hammering or stuttering sound in
the pipeline). Solenoid valve should be connected across Y1 and
COND on the interface board for all. Make sure that the VA draw
of the valve does not exceed the contact rating of the thermostat.
(See Fig. 4)
The water solenoid valve should be installed in the leaving water
line. A flow regulator valve should be located after the solenoid to
set the flow rate. The suggested flow rate is 1.5 GPM per ton if the
Entering Water Temperature (EWT) is 50
_
F or above. If below
50
_
F EWT use 2 GPM per ton. Example, a 4 ton unit with 50
_
F
EWT would require a 6 GPM flow regulator. This would be part #
FR6 (Flow Regulator) and the 6 is the GPM. If example was with
48
_
F EWT part. Refer to the
Open Loop Accessories
section in the
Geothermal System Components Catalog for more part numbers.
CAUTION
!
UNIT OPERATION HAZARD
Failure to follow this caution may result in equipment
damage or improper operation.
Discharge air configuration change is not possible on Heat
Pumps equipped with Electric Heat Option.
1
2
3
5
6
4
7
Typical Installation shown for
Illustrion purposes only.
Split unit not shown
9
8
10
11
12
13
14
Note
: Package unit shown. GZ unit is connected to furnace or fan coil (see page 6).
(1) Flex Duct Connection
(8) Hose Kits (optional)
(2) Low Voltage Control Connection
(9) Pressure Tank (optional)
(3) Vibration Pad
(10) P/T Ports
(4) Ball Valves
(11) Line Voltage Connection
(5) Solenoid Valve Slow Closing
(12) Electric Heater Line Voltage Disconnect
(6) Condensate Drain Connection
(13) Unit Line Voltage Disconnect
(7) Drain Valves
(14) Flow Regulator
A150775
Fig. 4 -- Example Well Water System Setup
