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Heat
ptmp bme
drop
ofthe
condensate
trap.
Vented
condensate traps
are
necessary
to break
the
negative
pressuro
in
the
air
chamber
and
allow
the condensate
to
flow.
Consffuct
condensate traps
to
the
following
diagram.
Air
v@t
3/4"Minim
di@til
2.
Open Loop Systems
On
an
open
loop
system the
design water temperature
will
be the
well
water temperature in
your
geographic region.
Many
cold climates
are
in
the
50oF
range
for well
water
temperature.
If
your well
water
temperafures
are
lower
than 50oF,
for
instance
Canadian
well
water
can be
as
low
as
43nF, the
flow
rate
must
be increased
to
avoid leaving
water
temperatures
below
the
freezing
point.
If
well
water
temperatures are above 50oF,
as
in
some
southern
states
where
well
water
temperatures are above 70oF, the
flow
rates
may
need
to
be increased
to dump
heat
more
efficiently in
the
cooling mode.
Varying well
water temperatures
will
have
little
effect on
unit
capacity
in
the
cooling
mode
(since the
well
is
connected
to
the heat
purp
condonser),
but
can have
large
effects on
the
capacity
in
the
heating mode (since
the
well
is
connected
to
the
evaporator).
If
well
water
temperafues
are
to
exceed 70oF,
special considerations,
such
as
closed
loop
systems, should
be
addressed.
B.
Building
Heat Loss/fleat
Gain
The
space
load
must be
estimated accurately
for
any
successful
HVAC installation.
There
are
many
guides
or
computer programs available
for
load estimation
including
the
ECONAR
GeoSource
Heat Pump
Handbook, Manual
J, and
others. After
the heat
loss/heat
gain is completed
and
loop
EWT
are established, the heat
pump
can
now
be selected
using the specifications
data.
Choose the
capacity
of
the heat
pump
based on
both
heating
and
cooling load.
VII.
ELECTRICAL
SERVICE
The main electrical service
must be
protected
by
a
fuse
or
circuitbreaker,
and be capable
ofproviding
the amperes
required by
the
unit
at
nameplate
voltage.
All
wiring
shall
comply with
the
national electrical
code
and/or
any
local
codes
that may
apply.
Access
to
the
line
voltage
contactor is
gained
through
the
knockouts provided
on
either
side
of
the heat
pump next to
the
front
corner.
Route
EMT
or
flexible
conduit
with
appropriate 3-
conductor
wire
to
the
contactor.
9WARNING
- The
unit
must
be
properlv erounded!9
VCIUTION:
Three-phase
units
ry[WI
be
wired
properly
to
insure
proper
compressor
rotation.
Improper
phasing may result
in
compressor damage.
An
electronic
phase sequence
indicator
must
be used
to check supply-
wiring
phase.
Also,
the
"Wild"
leg
of
the three-phase
power
must be connected
to
the
middle
leg
on the
contactor.
When supplying power to extemal water pumps
with
the
heat
pump's power supply,
use
only
impedance
protected
motors. ECONAR PumpPAKsru
can be
wired
directly
to
the
contactor
in
the
electrical
box.
The relay
will
energize
6"
Drop
rinirm
To
&aia
wilh
1/8"
pafoot
niHffipitch
3"
Rise
Figure
3
-
Condensate
Drain
-
Horizontal
and
Downflow Units Only
VI.
UNIT SIZING
Selecting
the
unit
capacity
of
a
geothermal
heat
pump
requires
two
things:
A)
Earth
Loop Configuration
and
Design
Water
Temperafures.
B)
Building
Heat Loss/Heat Gain.
A. Earth
Loop Configuration and
Design
Water Temperatures
Loop
configurations include
the open and closed
loop
varieties.
Heat pump capacity
and
flow
rate
requirements
vary depending
on
loop
configuration
(see
Table
3).
1.
Closed Loop Systems
Closed
loop
systems use
a
heat exchanger
of
high density
polyethylene pipe buried underground to supply
a
tempered
water solution back to
the heat
pump.
Closed
loops
operate
at
higher
flow
rates than open
loops
since
the
entering waler temperature
(EWT)
is
lower.
The
loop
EWT
supplied to
the heat
pump
has
a
great
effect
on
the
capacity
of
the
unit in
the
heating
mode.
Earth loops
in
cold climates
are
normally
sized
to supply
a
wintertime
EWT
to
the heat
pump
from
32oF
down to
25oF,
which
minimizes
the
installation
cost
of
the earth
loop
and
still
maintains proper
system
operation.
The
unit GPM
requirements
and pressure
drops
for
loop pump
sizilg
is
available
in
Table
3.
When
selectilg
the heat
pump,
choose
a
unit
that
will
supply
the necessary
heating or
cooling
capacity
at
the
minimum
and
maximum
earth
loop temperature
conditions
respectively.
Example;
if
a
residential
system
requires 45,000
Btu/hr
to
heat
a
house on an earth
loop
system (designed
for
32oF
minimum wintertime EWT),
and
36,000
Btu/hr
to cool
the house
on
an earth
loop
(designed
for
77oF
summertime
EWT),
a
Gx52x-x-Txxx
GeoSource 2000
heat
pump is required to handle
the
loads.
8
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