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cause
noisy operation
and
poor operating efficiencies
due
to lack
of airflow.
The
standard
GeoSource
DualTEK
(-Gxxxx-x-Dx0x)
heat
pumps
use
a
230
Volt
three-speed
blower.
For
maximum airflow,
the
blower
should
be
on
high
speed.
Moving
the
wire
on
the
fan
terminal
strip
can change the
fan speed. For
blower
data and
factory
settings,
see
Table
2._
An optional
variable
speed
ECM blower motor
is
available on
the
GeoSource
DualTEK (Gxxxx-x-DxVx)
series heat
pumps.
These
motors convert 230
Volt
AC
power to
DC
power
internally.
The DC power
can
then
be
modulated to
tum
the
motor
at
a
variety of
speeds.
The
blower's
speed
is modulated
based
on what
the
thermostat
is
calling
for. If
the
thermostat is
calling
for
only
the
FAN
to
operate, the
blower
will
put out
a
low
amount
of airflow in
cubic feet per minute
(CFM).
This
low CFM
output
will
gently circulate air throughout
the
house,
eliminating
hot or cold
spots, and
actually
reduce
the need
for
mechanical heating or
cooling
at
certain
times
of
the
year.
The
blower
can
supply this
minimal
CFM
output
with
a
very
low
electrical
usage.
When
the
thermostat calls
for
first
stage
forced air heating
or
cooling,
the
fan
speed
slowly
begins to
increase
speed.
Because
of
the
slow ramping
of
the
blower
speed,
full
speed on
first
stage
may not
be achieved
until
nearly
four
minutes
have elapsed
from
the
initial
call.
This
enables
the
blower
to
have
very quiet
starts, and
helps
minimize
cold
blasts
of
air
in
the
winter.
It
also
provides
increased
dehumidification in
the summer
and
warmer, more
comfortable discharge air
in
the
winter.
When
the
thermostat calls
for
second stage
heating,
it
will
bring
the
fan
speed
up to
high
speed. The fan
speeds
ofthe
GeoSource
DualTEK
heat
pumps
are
factory
set
to
provide
the
highest
efficiency
at
each stage
of
operation,
but may
be
adjusted
slightly in
the
field
to
increase
comfort.
These
settings
are
shown
in
Table
3.
The
controller
provides
a
total
of
12
fan
speed
set
points.
There
are
four different CFM
outputs
in
each
of
the three
fan
speed
ranges
(Low, Medium,
and
High).
These
CFM
outputs
are
factory
set, and
should
notbe
changed
in
the
field.
There is
an
Adjust
seuing,
which
allows
the
blower
to
be
operated
at+l- llVc ofthe
factory setting. For
example,
if
the
Adjust
tap
is
set
to
the
'1",
all
the
speeds
will
operate at90Vo
of
the
factory setting.
If
the
Adjust
tap
is
set
to
the
"+",
all
the speeds
will
operate
at
ll\Vo of
the
factory setting.
The
Adjust
tap
is
the
only
tap on the
Blower
Speed
Controller
that should
ever be
moved
from
the
factory setting.
The
blower
motor
also
provides
internal
circuitry
that
will
try
to maintain the setpoint
CFM
when
changes
occur
in
the
external static
pressure,
such
as
the
frlter
getting
dirty
over
time.
The motor
does
this
by
increasing its torque output to
compensate
for
external
resistance changes.
The
blower
is also
programmed
to
provide
soft starting to
reduce
air
noise,
delays after compressor shutdown to
distribute
all
the heat
output
from
the
compressor to
the
heated space, and
ramped
speed
changes.
All
these
features
are designed
for
quiet, comfortable,
efficient
operation.
eNote:
The
blower
will
not
operate
properly
if
ductwork
is not attached. The
ductwork
supplies static
pressure
to give
the
blower motor
a
load to
work
against.
Blower
motors may overheat
if
run
for
an
extended
period
of
time
without ductwork
attached.
Table
1-
Duct
Chart
Tables calculated
0.05
to
of
water
friction
per
At
these duct design
with
the pressure drop
the
filter,
3
4'
4x4
5
4x5,4x6
6"
4x8,4x6
7"
4x10,5x8,
6x6
8"
5x10,
6x8,4x14,7x7
9'
6x10,
8x8,4x16
10"
6x74,8x10,7x12
10"
6x20, 6x16,9x10
12"
6x18, 10x10,9x12
10'
'7x7
12"
6x20,8x14,9x12,10x11
10"
9x10. 8xl
2
10"
10x10,6x18,
8x12,7x14
t2"
6x20,7x18,8x16,
10x12
12"
8x18,
9x1
5,
10x14,
L2xt2
14"
10x1
8,
12114,8x24
16'
10x20,12x18,14x15
16',
lOtt
5, 12x20,
14x1
8,
15x16
18"
10x30,
15x18, 14x20
20"
1
0x35,
1
510,
16x19, 12x30, 14y25
20"
10x40, 12x30,
15x25, 18x20
22"
1
0x45, 15x28,
18x22, 2Ox20
the
total
design
extemal
static pressure
is
0.20 inches
of
water.
Normal
airflow
at 0.20 inches
of
water should then
be
used
for
these calculations.
:t:,&n*a:a
==t'iE*re:
lE€ffiry,€
%
50
75
1{Xt
150
2t{t
250
300
350
4{n
450
5{to
800
1000
12{tO
1400
1600
l n(xt
2000
22tYl
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