Electrical Service; Yiil 24Yolt Control Circuit; Transformer - Econar GeoSource Ultra GW Series Installation And Operating Instructions Manual

possible
hydronic heat
pump
applications,
but they
do
show
some important
principals
that can be applied to
any
system.
VTI.
ELECTRICAL SERVICE
e
Note
-
Always refer to
the inside
of
the
electrical box
cover
for
the correct wiring diagram,
and always refer
to
the nameplate
on the exterior
of
the
cabinet
for
the
correct
electrical specifications.
EWARNING -
ELECTRICAL SHOCK CAN
CAUSE
PERSONAL INJURY OR DEATH.
Disconnecr all
power
supplies before installing
or
servicing
electrical
devices.
Only
trained and
qualified service
personnel
should install,
repair or service this equipment.
9wanr,[n[c-
THE
uNrr
MUST BE
pRopERLy
GROUNDED!
The main electrical
service must
be
protected by
a
fuse
or
circuit
breaker and be capable
of providing
the
amperes
required
by
the
unit
at
nameplate voltage.
A11
wiring
must
comply
with
the national electrical
code and/or any local
codes that may apply.
Access
to
the
line
voltage contactor
is
through the knockouts
provided
on the side
of
the heat
pump next
to
the front
corner. Route EMT or flexible
conduit with
appropriate
size and
tlpe
of wire.
Ensure adequate supply wiring
to minimize
the
level of
dimming lights during
compressor startup on
single-phase
installations.
Some
dimming is
normal, and a variety of
start-assist accessories
are
available
if
dimming
is
objectionable.
elmportant
-
some models already have
a
factory-installed
start assist.
Do
not add additional
start
assists to those units.
9ClUffOn -
route
field
electrical
wiring
to
avoid
contact with
electrically
live
bare metal parts inside
the
elecfrical
box
and
to
avoid contact
with
the surface
of
the
factory-installed
start
assist
(if
provided).
VCAUTION
-
Three-phase
units must
be wired
properly
to
ensure proper
compressor rotation. Improper rotation
may result
in
compressor damage.
An
electronic phase
sequence
indicator must be
used
to
check supply-wiring
phases.
Also, the
"Wild-
1eg
of
the three-phase power
must
be connected to the
middle
leg
on the
contactor.
Important
- Only
the
ECONAR
PumpPAKrM is certified
to be wired directly
to the
compressor contactor and
can
be
grounded
in
the grounding lug for
208/230Yac. An
alternative loop pump or
a pump
for
a different
supply
voltage must be powered from a
separate
fused power
supply and controlled through
an
isolation relay that
has
its coil wired to
the
contacror circuit.
An
intemal pump relay provides the electrical
power
10
through the 3-pole terminal
block (BP)
for
rhe hydronic-
side circulator
pump.
The use of
impedance
protected
pumps eliminates the
need
for
additional fusing.
Do
not
comect
more than a 1/3 horsepower pump to
the internal
pump relay
terminal block.
eNote
-
The GW240
does
not have
aa
internal pump
relay.
A
pump for
the GW240,
or
a
pump larger than
1/3 horsepower on any other unit,
must
be
powered from
a
separate fused
power
supply
and
controlled through an isolation relay
that
has
its
24Vac
coil wired to
the
Y
and
X
terminals.
VIIII.
aAYOLT CONTROL CIRCUIT
Note -
Always refer
to the
inside
of
the electrical box
cover for
the
correct wiring
diagram.
There
are three basic sections
of
the
low
voltage circuit;
transformer, remote hydronic
confrols,
and controller.
A. Transformer
An
internal
transformer provides
24Yac
for all
control
features of
the heat
pump. Even though the transformer is
larger than the industry
standard,
it
is in
a
warm electrical
box
and can be overloaded
quickly. Table
5
shows
the
transformer
usage for
the
hydronic
heat pumps.
Table
5
- Transformer
@Important
-
If
the system's extemal conffols
require
more than shown
in
Table 5, an external transformer
and
isolation relays should
be
used.
Table
5
shows that
the
heat
pump's internal
transformer can
easily
power
the 24-
Volt
system.
In
contrast, Figure 4
shows
a
fan coil
system
with its own
power supply,
which
must interface
to
the
heat
pump to put
the
heat
pump into
the cooling
mode.
This can be
accomplished
by
using
the fan
coil's
independent
power supply
to
energize
the
coil
of
an
isolation
relay with
contacts located
in
heat
pump's
control circuit.
9WARNING
-
The GW240
uses a
large-capacity 24yac
Control
Transformer,
and
field
wiring to
remote
hydronic
conffols must be suitable for NEC
Class
1.
elmportant
-
Miswiring
of
24Yac control
voltage
on
system
controls
can result
in
transformer burnout.
elmportant
- Units with
a
dual voltage
ratfurg
(example,
208/230)
are
factory-wired
for
the
higher
volrage
7
t6
(2)
4
N/A
18
lz
2
I
Nre
4 (2)
Ll2
2
10 10
33VA
50
72YA
150
)
Component
37-87
240
Contactor
Pump Relav
Reversins
Valve
8
Controller
20-1038
Contactor Pilot
Relavs
Plug Accessory (PA)
Total
Transformer
VA
size