Bard GV27S1-A Installation Instructions Manual - page 16
Manual 2100-510E
Page
16 of 38
MIS-2621
1" FLEXIBLE HOSE
HOSE CLAMPS
WATER IN
WATER OUT
GROUND LOOP
PUMP
WALL BRACKET
FIELD-FABRICATED
PIPE TO GROUND LOOP
PIPE FROM
MODULE
OPTIONAL VISUAL
FLOW METER
NOTE: IF USED
SUPPORT WITH A
STRAIGHT BARBED
BRASS ADAPTERS
GROUND LOOP
(EARTH COUPLED WATER LOOP APPLICATIONS)
FIGURE 6
CIRCULATION SYSTEM DESIGN
NOTE:
Unit shipped from factory with 60 PSIG low pressure
switch wired into control circuit and must be rewired to
45 PSIG low pressure switch for ground loop
applications.
This unit is designed to work on earth
coupled water 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.
The heat pump itself is rarely the cause. Most problems
occur because designers and installers forget that a
ground 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 work sheet to simplify heat loss
calculations and circulator selection. Refer to
“Circulating Pump Worksheet” section in manual
2100-099.