Econar GeoSource Vara GV Series Installation And Operating Instructions Manual page 5

A
variable
speed
ECM blower
motor is
used on
the
GeoSource
Vara
series heat
pumps.
These
motors
convert 230
Volt
AC power to DC power
internally.
The
DC power
can then be
modulated to turn
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
heating or
cooling,
the fan speed
slowly
begins to increase
speed.
Because
of
the
slow ramping of
the
blower
speed,
fuIl
speed on
frst
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
summer.
It
also
provides
increased
dehumidification in
the sufirmer
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
Vara
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
cornfort.
These settings
are
shown in Table
2.
Table
1-
Duct Chart
Tables calculated for 0.05 to 0.10 inches
ofwater friction
per
the total design external static pressure is
0.20 inches
of
water.
Table
2 -
Airflow
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 not
be changed
in
the
field.
There is
an
Adjust
setting,
which
allows
the
blower
to
be operated
at+/-
lU%o
ofthe
factory setting. For
example,
if
the
Adjust
tap
is
set
to the
"-*,
all
the
speeds
will
operate at
90%o
of
the
factory setting.
If
the
Adjust
tap
is
set
to the
"+",
all
the speeds
will
operate
atll}%a 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
filter
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 oulput
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 without
a
load
if
run for
an
extended
period of
time.
At
these duct design conditions,
along
with the pressure drop
the fi1ter,
4"
4x4
7S
5" 4x5,4x6
6"
4x8,4x6
150
7"
4x10, 5x8, 6x6
200 5x70,6x&,4x14,7x7
250 6x10, 8x8,4x16
10"
6x14, 8x10,7x12
350 10" 6x20, 6x16,9x10
1.2"
6xi8, i0x10,9x12
10" 4x20,7x10,6x12,
8x9
1.2
6x20, 8x14, 9x12.
10x1
1
I0"
5x20,6x16,9x10,
8x12
s00
10"
10x1 0, 6x1 8, 8x1,2,
7
x14
72" 6x2O,7x78,8x16,
10x12
800
12"
8x1
8,
9x15, 10x74, 72x12
14" 10x18, 12x14,8x24
t200
16"
10x20,12x18,14x15
1400 16" 10x25,
1,2x20, 14x1
8,
15x1
6
18"
10x30, 15x18, 14x20
1800 20"
10x35, 15x20,
1,6x19,
12x30. 74x25
2000
20"
10x40,
12x30, 15x25,
18x20
GV/GrV360/361
485
1
100
12t0
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680
1550
1
705
GV/Grr/590/591
790
1
800 1920
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845
7920
2000
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