Transformer; Wiring; 4-Way Valve Control - Econar GeoSource Vara GV Series Installation And Operating Instructions Manual

VilI.}4YOLT
CONTROL
CIRCUIT
The
wiring diagram
in Figure 4
shows the
low
voltage
controls
of
the heat
pump. This
section
will
break down
the three
basic components
of
the
low voltage
circuit;
transformer, thermostat,
and
conffoller.
A. Transformer
An
electrical diagram is provided in Figwe 4,
and on the
electrical box cover panel of
the heat
pump. An internal
24-volt,55
VA transformer is provided to
operate
all
control
features
of
the heat
pump.
Table 4 shows the
transformer usage
for
GeoSource
Vara
heat pumps.
If
any system's extemal controls require more than the
VA
available
for
extemal use
from the transformer,
a
separate
transformer must be used.
The
heat
pump's
transformer can
generally power simple external control
systems
consisting
of
a
few
relays
or
a zone
valve
(depending, of course, on the
VA
draw of
the
components). On more complicated
control systems the
transformer's capactty is
used
up very
quickly.
€Note:
For units operating on
208V electrical service,
the transformer must
be switched to
the
correct lead (see
electrical diagram -
Figure
4).
Units
are
factory shipped
with the
fansformer
set
for 240V service.
Operating a
unit
on
208V with the transformer
set
to 240V
will
cause
the
unit to
operate
with lower
than
normal control voltage.
Table
4
- Transformer
B. Thermostat
A
2-heatl
I
-cool thermostat,
ECONAR part number
70-2002, is required
for proper operation
of
GeoSource
Vara
heat
pumps. This thermostat controls
all
stages
of
operation
of
the heat
pump.
Initiation of each stage is
implemented based on the
recovery
rate
of
the
actual
temperature to the
set
point temperature. This means that
switching to
a
higher
stage
will
require time (sometimes
15
minutes or more) for
the
thermostat to calculate rate
of
change.
Consult the
instructions
in
the thermostat box
for
proper mounting
and
operation. Be careful
to
select a
thermostat
location where extemal temperature sources
^)
will
not
effect
sensed
temperature.
V ClUffON-
miswiring of control voltage on system
controls
can
result
in
fuse
or transformer burnout.
€Note:
If
a
single thermostat controls
multiple
heat
pumps,
the
control wiring of
the heat
pumps
must be
isolated from
each
other. This
will
prevent
the
heat
pumps from
receiving
high voltage
though
the common
wiring
if it
is tumed
off
at the
circuit breaker
for
service.
1.
Wiring
Eighrwire thermostat cable must be
run from
the heat
pump to
the
thermostat.
Power is supplied to
the
thermostat by connecting the
R and
X
(C) terminals to
the
heat
pump terminal
strip.
The G terminal
from
the
thermostat initiates the
blower's sequences. The
fust
stage
operation is energized by the
Y terminal.
The
unit
is
put into
the
cooling mode when
the
thermostat
energizes the
O
terminal, which
operates the
4-way
reversing
valve.
The W2 terminal energizes second stage
heating
if
present.
The E terminal energizes the
backup
heat source
(if
present)
in
emergency heat
mode. The
L
terminal
is connected
to
an
LED
on the
thermostat.
These
connections
are
listed
in Table
5.
Table
5
-
Connections
2.
Lights
The
L terminal
on the heat
pump, wired to
the
L terminal
on
the
thermostat,
will light
the
"lockout"
light on
the
thermostat;
indicating
the
controller is
in lockout
mode.
If
this occurs, please
see
the
section titled "Compressor
Lockouts."
C.
Controller
The
controller
receives a
signal
from
the
thermostat and
initiates
the
correct sequence
of operations for
the heat
pump.
The controller performs
the
following
functions:
1)
Blower Operation and
Speed
Control
2)
Earth
Loop
Pump
Initiation
3)
CompressorOperation
4)
4-Way Valve Control
5)
Compressor Lockouts
6)
CompressorAnti-Short-Cycle
7)
System
Diagnostics
8)
Overflow Detection
1.
Blower Oferation
and Speed
Control
A
signal on the G
terminal from
the
thermostat to the
controller
will tell
the
controller to
energize the
blower.
A
G signal
alone
puts
the
motor
in
low
speed
operation.
If
the
thermostat
sends a
G and
Y
signal to the
controller
for
1't stage
operation, the
controller
bumps the
blower
speed
up to
Medium.
When the thermostat sends
a
G,
Y,
9
R
R
x
c (x)
G G
o
o
Y1 Y1
L L
w2 w2
E E
lctor 7
y Valve 4
2
rostat
1
,
M"t..
2
at Relay
(opt.)
6
22
33
Slir*BffiIS{fiii
Tlcrssstd
Frmt6oa
24
Volt
Power
Common
Blower
Reversing
Valve
1"
Stage
Heat
/ Cool
Lockout Simal
2'd
Stage
Heat
Emerqency Heat
Coxgloneot.
YA
Controller
Iotal
Available