Specifications

Manual 2100-317
Page 17
MIS-1213
CLOSED LOOP
(Earth Coupled Ground Loop Applications)
NOTE:
Unit shipped from factory with 27 PSIG low
pressure switch wired into control circuit and
must be rewired to 15 PSIG low pressure switch
for closed loop applications. This unit is designed
to work on earth coupled ground loop systems,
however, these systems operate at entering water
(without antifreeze) temperature with pressures
well below the pressures normally experienced in
water well systems.
THE CIRCULATION SYSTEM DESIGN
Equipment room piping design is based on years of
experience with earth coupled heat pump systems. The
design eliminates most causes of system failure.
Surprisingly, the heat pump itself is rarely the cause.
Most problems occur because designers and installers
forget that a closed loop earth coupled heat pump system
is NOT like a household plumbing system.
Most household water systems have more than enough
water pressure either from the well pump of the
municipal water system to overcome the pressure of head
loss in 1/2 inch or 3/4 inch household plumbing. A
closed loop earth coupled heat pump system, however, is
separated from the pressure of the household supply and
relies on a small, low wattage pump to circulate the water
and antifreeze solution through the earth coupling, heat
pump and equipment room components.
The small circulator keeps the operating costs of the
system to a minimum. However, the performance of the
circulator MUST be closely matched with the pressure of
head loss of the entire system in order to provide the
required flow through the heat pump. Insufficient flow
through the heat exchanger is one of the most common
causes of system failure. Proper system piping design
and circulator selection will eliminate this problem
Bard supplies a worksheet to simplify head loss
calculations and circulator selection. Refer to
“Circulating Pump Worksheet” section in manual
2100-099.
FIGURE 6
1” FLEXIBLE HOSE
WATER OUT
OPTIONAL VISUAL
FLOW METER
NOTE: IF USED
SUPPORT WITH A
FIELD-FABRICATED
WALL BRACKET
HOSE CLAMPS
WATER
IN
PUMP
MODULE
PIPE FROM
GROUND LOOP
PIPE TO GROUND LOOP
BARB X INSERT
BRASS ADAPTERS