Hybrid
Vertical
Stack
–
Installation
Operation
Maintenance
Manual
OPERATION
‐
DETAILED
R090303
Installation
Operation
Maintenance
Manual
is
subject
to
change
without
notice
Page
14
Note
:
The
last
flash
code
will
be
maintained
in
memory
for
1
week
or
until
the
unit
controls
are
powered
down.
The
flash
code
will
continue
until
the
problem
has
cleared
and
the
compressor
has
been
put
into
operation.
If
a
cooling
call
is
in
place,
it
must
be
disengaged
before
the
cause
of
the
last
alarm
shutdown
can
be
identified.
OPERATION
ALGORITHM
There
are
several
control
algorithms
to
prevent
cycling
and
problematic
operation.
These
are:
1.
Double
Call
–
If
thermostat
connections
or
set
up
is
incorrect
resulting
in
a
simultaneous
call
for
both
heating
and
cooling,
the
unit
will
not
operate.
This
condition
can
be
observed
on
the
thermostat
connection
LEDs.
(Note:
A
heat
pump
thermostat
will
present
this
scenario)
2.
Reverse
Cycle
Call
–
Poorly
located
automatic
changeover
thermostats
(ie.
thermostats
mounted
on
a
wall
opposite
a
discharge
grill,
or
a
thermostat
in
a
doorway
to
outside)
can
trigger
heating
and
cooling
mode
changes
many
times
an
hour.
The
CGC
controller
has
a
10
‐
minute
anti
‐
mode
change
timer
for
both
heating
and
cooling
mode
changes.
The
controller
will
not
accept
a
change
in
mode
until
10
minutes
have
elapsed
since
termination
of
the
opposite
call.
THERMOSTAT
CONNECTIONS
The
CGC
control
board
has
been
designed
to
operate
with
most
standard
24V
AC
thermostats.
These
are
powered
from
the
CGC
board
with
24V
AC
and
simply
switch
power
ON
to
each
of
the
Heat
(W),
Cool
(Y),
Fan
(G)
or
Aux
(A).
While
most
present
day
thermostats
operate
in
this
manner
there
are
others
that
may
or
may
not
work
properly.
The
following
should
be
checked
out
for
satisfactory
performance
prior
to
installation:
1.
Heat
Pump
Thermostat
–
Some
heat
pump
units
do
not
have
heat
relays
(therefore
are
not
compatible
with
standard
thermostats)
and
require
“Heat
Pump
Thermostats”.
These
thermostats
call
for
both
heating
and
cooling
on
one
of
the
signal
wires.
These
thermostats
are
completely
incompatible
with
CGC’s
controller.
2.
Mercury
bulb
thermostat
‐
This
type
is
problematic
but
can
be
used.
Unfortunately,
the
anticipators
are
a
problem.
Heat
anticipators
must
be
in
series
with
a
high
current
relay
or
valve
to
function,
so
do
not
perform
on
an
electronic
circuit.
This
will
result
in
larger
than
normal
temperature
swings.
The
cool
anticipator,
if
oversized,
can
bleed
enough
current
to
indicate
a
cooling
call
even
after
it
has
been
terminated.
3.
Battery
powered
thermostats
–
These
thermostats
were
developed
as
replacements
for
old
mercury
bulb
thermostats
that
had
4
wire
connections
while
24V
electronic
