Bard STAGED CAPACITY PACKAGED HEAT PUMP QW5S1 - Manual (Page 30)

Manual 2100-532B
Page
30 of 46
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
FIGURE 19
CIRCULATION SYSTEM
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 head loss
calculations and circulator selection. Refer to
“Circulating Pump Work sheet” section in manual
2100-099. Loop pump performance data can be seen in
Figures 21 and 22.
COPPER WATER COIL APPLICATION
Copper water coils are available as a factory installed
option. The unit model number will indicate the coil
option as the next to last character; “C” represents a
water coil constructed of copper material and “N”
represents a water coil constructed of cupronickel.
The cupronickel coil is suitable for all applications.
The copper coil is suitable for applications using
ground loop and cooling tower only and is not
recommended for open well application.
CLOSED LOOP
(Earth Coupled Ground Loop Applications)
OUT
MIS-2748
for Model No.)
(See Spec Sheet
FLEXIBLE HOSE
PIPE FROM
GROUND LOOP
PUMP MODULE
PIPE TO
GROUND
LOOP
WATER