13
R e s i d e n t i a l D i g i t a l P a c k a g e d U n i t s G T- P B S e r i e s - 6 0 H z P u ro n
®
R e v : 4 A p r i l , 1 4
Figure 15b: Valve Position B - Unit Fill / Flush
Loop
Valve Position
Out
In
Flushing the Earth Loop
Flush Port
Front of Unit
Valve Position
Figure 15d: Valve Position C - Full Flush
Loop
Valve Position
Dead Head
Pump Test
for Air
Add Antifreeze
Now if Needed
Out
In
Flush Port
Front of Unit
Valve Position
Unit Fill
Unit
fi
ll valves should be switched to Position B while
fl
ush
cart is pumping to
fi
ll the unit heat exchanger (see Figure
15b). The valves position should be maintained until water is
consistently returned into the
fl
ush reservoir.
Loop Flush
Switch to valve Position A. The supply water may be shut off
and the
fl
ush cart turned on to begin
fl
ushing. Once the
fl
ush
reservoir is full, do not allow the water level in the
fl
ush cart
tank to drop below the pump inlet line or air can be pumped
back out to the earth loop. Try to maintain a
fl
uid level in the
tank above the return tee so that air can not be continuously
mixed back into the
fl
uid. Surges of 50 psi [345 kPa] can
be used to help purge air pockets by simply shutting off
the
fl
ush cart return valve going into the
fl
ush cart reservoir.
This process ‘dead heads’ the pump to 50 psi [345 kPa]. To
dead head the pump until maximum pumping pressure is
reached, open the valve back up and a pressure surge will
be sent through the loop to help purge air pockets from the
piping system. Notice the drop in
fl
uid level in the
fl
ush cart
tank. If all air is purged from the system, the level will drop
only 3/8” in a 10” [25.4 cm] diameter PVC
fl
ush tank (about
a half gallon [1.9 liters]) since liquids are incompressible. If
the level drops more than this level,
fl
ushing should continue
since air is still being compressed in the loop
fl
uid. Do this a
number of times.
NOTICE: Actual
fl
ushing time require will vary for each
installation due to piping length, con
fi
guration, and
fl
ush
cart pump capacity. 3/8” or less
fl
uid level drop is the ONLY
indication that
fl
ushing is complete.
Switch valves to Position B to
fl
ush the unit. Flush through
the unit until all air pockets have been removed.
Move valves to position C. By switching both valves to this
position, water will
fl
ow through the loop and the unit heat
exchanger. Finally, the dead head test should be checked
again for an indication of air in the loop. Fluid level drop is
your only indication of air in the loop.
Pressurize and Operate
As shown in Figure 15e, close the
fl
ush cart return valve
to pressurize the loop to at least 50 psi [345 kPa], not to
exceed 75 psi [517 kPa]. Open the isolation valve to the
expansion tank and bleed air from the expansion tank piping
using the schraeder valve located in front of the expansion
tank. This will allow loop pressure to compress the
expansion tank bladder, thus charging the expansion tank
with liquid. After pressurizing, close the
fl
ush cart supply
valve to isolate the
fl
ush cart. Move the Flow Controller
valves to Position D.
Loop static pressure will
fl
uctuate with the seasons and
pressures will be higher in the winter months than during
the cooling season. This
fl
uctuation is normal and should
be considered when charging the system initially. Unhook
Содержание 50YFH
Страница 2: ...This page was intentionally left blank ...
