Econar GeoSource DualTEK GV Series Installation And Operating Instructions Manual page 12

Table
6
-
Side
Flow
Rates
Pressure/Temperature
(P/T) ports should
be
installed
in
the entering
and
leaving water lines of
the heat
pump on
a
closed loop
system (see
Figure4). A
thermometer
can be
inserted into
the
P/T ports to
check
entering
and
leaving
water temperatures.
A
pressure gauge can also be
inserted into
these
P/T ports to determine
the pressure
differential
between
the
entering
and
leaving water. This
pressure differential
can then be
compared to
the
specification
data on each
particular
heat
pump to
determine the
flow
rate
of
the svstem.
A
PumpPAKrM that is
individually
sized
for
each
application
can
supply pumping requirements for
the
earth loop
fluid.
The PumpPAKrM
can also be used
to
purge
the
loop
system. The PumpPAKrM is wired directly
to
the
contactor
and operates
whenever
the compressor
runs (see Electrical Diagrams
-
Figures
8 and
9).
If
a
PumpPAKrM
is
not
used, a separate
pump
can be used
which
is
energized with
a
pump relay (note: electrical
code
will
require
a
fused disconnect
for pumps other than
PumpPAKsrM).
Filling
and
purging
a
closed
loop
system are
very
important
steps
to
assure
proper
heat
pump operation.
Each loop must be
purged with
enough water
flow
to
assure a
two feet per
second
flow
rate
in
each
circuit
in
the
loop.
This normally requires a
lYz
to
3 HP high head
pump to circulate
fluid
through
the
loop
to
remove all
the
air out of
the
loop
and
into
a
purging tank. Allow
the
pump to run
10
to
15
minutes after
the
last air bubbles
have been
removed.
Enough
antifreeze
must
be added to
give a
10oF
to
15oF freeze
protection to
the earth
loop
system. This amount should
be
calculated
and added
to
the
loop
after purging is
complete.
After
antifreeze
has
been installed
it
should
be measured
with
a
hydrometer,
refractometer or
any
other device to determine
the
actual
freezing
point of
the solution. Remember that
a
low
arftifreeze
level
will
lock
the heat
pump out on low
pressure during wintertime operation.
The
purge
pump
can be used to pressurize the
system
to
an
initial
static pressure of 30-40
psi.
Make
sure the
system
is
at
this pressure after
the
loop pipe
has
had
enough time
to stretch. In
order to
achieve the 30 to 40
psi initial
pressure, the loop may
need to
be
pressurized to
60 to 65
psi.
This
static pressure
will
fluctuate from
heating to
cooling
season,
but the pressure
should always
remain
above
zero
so
circulation
pumps do not cavitate
and
air
cannot be
pulled into
the system.
SFor
information
regarding
earth
loop
installations contact
your
local installer, distributor
or factory representative.
B.
Open Loop Applications
An open system gets its
name
from
the open discharge
of
water after it
has been used
by
the heat
pump. A
well
must be available that can supply all of
the water
requirements
(see Table 6)
of
the heat
pump along with
any
other water requirements drawing off
that same
well.
The
well
must
be capable
of
supplying the heat pump's
required
flow
rate for up to 24
hours
per day on
the
coldest winter
day.
Figure 5 shows the necessary
components
for
water
piping of
an
open system. First,
a
bladder type pressure
tank with
a
"draw
down" of
at
least
lYz times the well
pump capacity
must be
installed
on the supply
side
of
the
heat
pump.
Shut
off
valves
and
boiler
drains
on the
entering and leaving water lines
are
necessary for future
maintenance issues.
A
screen
strainer
is
placed
on the
supply
line with
a
mesh size
of
40 or 60
and enough
surface area to allow for
particle
buildup
between
cleanings.
Pressure/Temperature
(P/T) ports
are
placed in
the
supply
and
discharge lines
so
that thermometers or pressure
gauges can be inserted into
the water
stream.
On the
well
water discharge
side
of
the heat
pump,
a
flow
control valve must
be mounted next to the heat pump to
regulate the
maximum
water
flow
through
the
unit. A
solenoid valve is
then installed and wired to the accessory
plug
(P2) on
the
controller.
This valve
will
open
when
the
unit
is
running
and close when
the
unit
stops.
A
visual
flow
meter is then installed to allow visual
inspection
of
the
flow
requirements. The
flow
meter
is
useful in
determining when maintenance is required.
(If
you
can't
read
the
flow,
cleaning is required.
See
Water
Coil Maintenance for
cleaning instructions.)
Schedule
40 PVC piping,
copper tubing, polyethylene or
rubber
hose can be used
for
supply
and
discharge water
lines.
Make
sure
line
sizes are large
enough to supply the
required
flow
with
a
reasonable pressure drop (generally
1" diameter
minimum). NOTE:
Do not
use
plastic
female fittings with
metal male fittings,
or fractures may
result in
the female
fittings.
Always
use
plastic male into
steel female!
Water
discharge
is generally
made
to
a
drain
field,
stream,
pond,
surface discharge,
tile line,
or storm
sewer.
VCAUTION:
Using
a
drain
field
requires soil
conditions
and adequate sizing
to
assure
rapid percolation,
or
the
required flow
rates
will
not
be
achieved.
Consult
local
codes and ordinances to
assure
compliance.
p
pf
discharge water to
a
septic
system.
10
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