Z4Yolt Control Circuit; Transformer - Econar GeoSource 2000 GV Series Installation And Operating Instructions Manual

L
the PumpPAKrM
with
a
call for
heating or
cooling.
The
use
of
impedance
protected pumps eliminates
the need
for
additional
fusing
on the PumpPAKrM.
VIII.
}AYOLT
CONTROL
CIRCUIT
The
wiring
diagrams in Figures 5
and
6
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
controller.
A. Transformer
Electrical
diagrams
are
provided in Figures
5 and
6
and
on the
electrical box cover panel of
the GeoSource 20(X)
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 usase
for
GeoSource 2000
heat pumps.
Table
4
- Transformer
If
any system's external controls require more than the
VA
available
for
external
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
transformers capacity is
used
up very
quickly.
cNote:
For units operating on 208V electrical
service,
the
transformer
must be
switched to
the
correct lead
(see
electrical diagram - Figures 5 and
6).
Units
are
factory
shipped
with
the
transformer
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 voltages.
B. Thermostat
A2-heatll-cool
thermostat is recommended for proper
operation
of
GeoSource
2fi)0
heat
pumps. Eight wire
thermostat cable
is
required
for
proper operation of
the
thermostat. Consult
the instructions
in
the thermostat box
for proper mounting
and
thermostat operation.
V
C.LUffON-
miswiring of control voltage on
system
controls can result
in
fuse
or
transformer burnout.
eNote:
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 through
the common
wiring
if it
is tumed
off
at the circuit breaker
for
service.
Power is supplied to
the
thermostat by connecting
the R
and
X
terminals to the heat
pump terminal strip.
The
fan
is controlled
through the G
terminal
and
will
operate
continuously in
the
FAN ON position or
when
the
compressor
is
running
in
the
FAN
AI-ftO position.
The
Y
terminal
energizes the
compressor. The unit
is
put into
the air
conditioning
mode when
the
thermostat
energizes
the
O terminal, which
operates the
4-way reversing valve.
A
lockout condition
is
indicated by
the
L
terminal, which
lights
a
red light
on the
thermostat (depending
on the
thermostat). This lockout condition
means
that
the
unit
has shut
itself down on
a
low or high-pressure switch
to
protect itself,
and
will
not
come back on
until power
has
been reset
to
the heat
pump. If
a
lockout condition
exists,
the heat
pump should not
be reset more than
once.
A
service technician should
be
called immediately.
Repeated reset can
cause dama-ee
to the system.
If
second stage
heating (e.g. electronic
resistance
strip
heat) is used,
its control wiring
is connected to
X
and
W2
on the heat
pump terminal
strip.
Fan
interlock relays
are
not required
since the
thermostat
energizes the
blower
whenever the second stage is
calling. W2
on the terminal
strip is wired directly to
second stage
heating
on the
thermostat. In
the event
of
a
heat
pump shutdown,
switching
the
thermostat to emergency
heat energizes the
E terminal, which runs
the
blower
and second stage heater
but
does
not energize the compressor. The thermostat
will
indicate whenever
second stage
heating is
energized.
These
wiring connections
are
listed in Table
5.
Table
5
-
Connections
Use
of
a
programmable
setback thermostat
in
conjunction
with
a
geothermal
heat
pump
and a second stage
backup
electric
resistance heater
has
the
potential to
cause
inefficiency.
The energy savings supplied by
ni-eht
setback could be less
than
the energy used
by
the
electric
elements
if
they
operate
in
the
moming
to warm the space
to
the
daytime temperature setting.
Second stage usage
should be
monitored and
setbacks
adjusted to maximize
energy savings of
the
entire
system.
eNote: If
the thermostat is
provided by
others and is
equipped
with
an anticipator,
it
should be
set
to its highest
setting to avoid
interfering with
heat
pump operation.
9
Contactor
1
7
x2
4-Way Valve
4 4
Controller
')
2
Thermostat I
1
Blower Relay
6
6x2
Electric
Heat Relay
(optional)
6
NA
Total 26 JJ
Available
29 22
R R 24 Volt Power
Common
x
c(x)
Blower
G G
Reversing
Valve
o o
1"
Stase
Heat/Cool
Y1
YI
Lockout
Sisnal
L
L
2oo
Stage Heat
w2 w2
Emergency Heat E E
\
L
Comoonent
18{7
98-12{'
Functiog Terminal
Strip
Tlrermostat