Bosch Geothermal Heat Pumps Applications Manual page 96

9 6 | Bosch Geothermal Heat Pumps
3. Once all debris is removed make sure the return hose
is below the reservoir water level. Continue running
the ush cart pump while observing any air bubbles
in the reservoir (Figure 113). "Dead head" the pump
every so often (surges of 50 PSI) and watch the water
level in the reservoir (once all the air is removed there
should not be more than a 1" to 2" drop in water level
in the reservoir). If there is more than a 2" drop, air
is still trapped in the system. The uid level drop in
the reservoir is the only indication of air in the ground
loop.
Fig. 113 Flush cart step 3
Antifreeze may be added before, during or after the
ushing procedure. However, depending upon which
time is chosen, antifreeze could be wasted when
emptying the ush cart reservoir.
Purge the ground loop for approximately 2 hours.
Once all air is removed from the ground loop, turn the
3-way valve to the ush port/unit position and repeat
the purging process. The unit side purge should only
take approximately 5 to 10 minutes. While the ush
cart pump continues to run, turn the 3-way valve to
the ush port/unit and loop position (Fig. 114). Once
ushing and purging is complete the system can be
pressurized.
Data subject to change
Fig. 114 Flush cart step 4
Always operate the Bosch geothermal heat pump
system in either the heating or cooling mode as
necessary for a few minutes to condition the ground
loop to a homogenous temperature. During this
time, installers should perform tool cleanup, piping
insulation, etc.
4. Now the nal pressurization of the ground loop can
be performed (Fig. 115). Close the return line ball
valve (dead-head the pump). Allow the ush cart
pump to run until there is approximately 50 - 75 PSIG
(winter) or 35-40 PSIG (summer) of pressure on the
system (whatever the ush cart pump is capable of
producing). Turn the return side 3-way valve to the
unit/loop position. Turn the supply side 3-way valve to
the unit/loop position. Turn the ush cart off, remove
the hoses and return the caps to the ow center.
Applications Manual
Bosch Thermotechnology Corp.