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R-J11 CONNECTOR (E109)
WARNING
DO NOT CONNECT A TELEPHONE
OR PHONE LINE TO THE CONNEC-
TOR (JACK) AT POSITION E109.
DOING SO COULD CAUSE
IRREPRABLE DAMAGE TO EITHER
THE FURNACE CONTROL (I.F.C.) OR
THE TELEPHONE (OR TELEPHONE
LINE) OR BOTH.
This connector is used to program the
furnace control at the factory. It can
also be used to connect a field service
diagnostic tool. Unfortunately, this tool
was not available at the time of this pub-
lication but should be available in the
future. Otherwise, this connection is not
to be used in the field. It should never
be connected to a telephone line or a
telephone. Doing so could damage the
furnace control or the telephone (or tele-
phone lines) or both.
COMMUNICATIONS
NETWORK CONNECTIONS
These connections are used when
installing a communicating thermostat
specified for use with this furnace.
Further, normally, thermostat connec-
tions will not be made at the legacy 24
V Thermostat Inputs when using a com-
municating thermostat. (Except under
one special circumstance where a com-
municating thermostat and non-commu-
nicating condenser are used. (See
Figure 38 and the section of this docu-
ment titled SPECIAL CONFIGURATION
– COMMUNICATING THERMOSTAT
AND FURNACE WITH A NON-COM-
MUNICATING CONDENSER.)
The terminal labeled "1" on the furnace
control connects directly to the terminal
labeled "1" on the thermostat and "1" on
the condenser. The remaining connec-
tions follow the same pattern.
Follow the wiring diagram in Figure 37
for connections of the communications
network.
COMMUNICATIONS L.E.D.'s
(Light Emitting Diodes)
Note: The " RX" and " STAT" L.E.D.'s
will not operate unless a communi-
cating thermostat is installed. These
L.E.D.'s will not energize if a tradi-
tional 24V thermostat only is used to
control the furnace.
" RX" (Green) L.E.D. – This L.E.D. indi-
cates that communications is being
sensed to or from (i.e.: something on
the network is trying to communicate)
other components (e.g. a condenser) on
the network. This L.E.D. will blink ran-
domly any time a message is received
by the furnace control. If no blinking is
seen within five minutes, it can be
assumed that there is not valid commu-
nications established. Check wiring to
make sure that all points are connected
properly.
Further, if this L.E.D. is on continuously,
it is an indication that mis-wiring has
occurred. Most probably, connections
"1" and "2" are reversed. Double-check
the wiring and make sure that the wire
connected to pin "1" on the condenser
is the same wire connected to pin "1"
on the thermostat and the furnace con-
trol. The same follows for the wires to
pins "2", "R" and "C".
" STAT" (STATUS) (Red) L.E.D. – This
L.E.D. blinks twice slowly (¼ second
ON, ¾ second OFF) upon power-up.
LEARN BUTTON
Pressing the learn button for two sec-
onds will cause the green "RX" L.E.D.
to blink rapidly (for a short period) to
indicate an attempt at communications.
If the L.E.D. does not blink, communi-
cations can not be established. The
problem may be that the wires at the J9
connector "1" and "2" on the I.F.C. may
be reversed. Check to make sure that
wiring is from "1" on the IFC leads to
"1" on the thermostat and condenser (if
present) and the same follows for con-
nections "2", "R" and "C".
MEMORY CARD
CONNECTOR (E117)
This connector is used to insert a mem-
ory card.
MEMORY CARD
A memory card is defined as an elec-
tronic card that carries a copy of the
furnace shared data.
RULES FOR WRITING, DISTRIBU-
TION AND ARBITRATION OF MULTI-
PLE COPIES OF FURNACE SHARED
DATA FOR COMMUNICATING-CAPA-
BLE FURNACES
Furnace shared data is defined as data
specific to a given furnace that is criti-
cal for proper furnace operation. More
specifically, it is data which defines the
operation of the furnace and is unique
to a given furnace platform and model.
The most critical of these data are the
coefficients that control the blower
operation (i.e. define the blower speed-
torque operation). Because of this,
each furnace control is programmed
with furnace shared data for that model
furnace only. The furnace shared data
from any given furnace can NOT be
transferred to another furnace for any
reason. Doing so can adversely affect
operation of the furnace. Further, if no
furnace shared data is present, the fur-
nace will not operate in any mode and
a fault will be displayed.
Valid Furnace Shared Data is
defined as furnace shared data for
the furnace series in question with
the correct motor horsepower.
However, it is impossible for the fur-
nace control to determine if the fur-
nace shared data is matched to the
furnace input BTU's if the motor
horsepower is correct. This means,
for example, furnace shared data for
a 120KBTU upflow furnace could be
installed and recognized as valid fur-
nace shared data in a 90KBTU
downflow furnace. VALID FURNACE
SHARED DATA simply means that
there is no motor horsepower con-
flict and that the furnace shared data
is for the series of furnace in ques-
tion. VALID FURNACE SHARED
DATA is data that will be used by the
furnace control with no fault report-
ed. VALID FURNACE SHARED
DATA may not necessarily mean
that the furnace shared data is cor-
rect for the furnace in question. The
input BTU's could still be incorrect
and this is why it is important to
never exchange memory cards from
one furnace to another.
Furnace shared data is programmed
into the furnace control microproces-
sor and attached memory card at
the factory. The attached memory
card cannot be programmed in the
field but furnace shared data inside
the furnace IFC microprocessor may
be written or rewritten in the field
through the network depending on
the circumstances.
WARNING
DO NOT REPLACE THE FURNACE
CONTROL OR MEMORY CARD OF
THE FURNACE WITH A FURNACE
CONTROL OR MEMORY CARD OF
ANOTHER FURNACE OR ANOTH-
ER COMPONENT (E.G.: A MEMO-
RY CARD FROM A CONDENSER
OR AIR HANDLER). THE WRONG
FURNACE CONTROL OR MEMO-
RY CARD MAY SPECIFY PARA-
METERS WHICH WILL MAKE THE
FURNACE RUN AT UNDESIRED
CONDITIONS INCLUDING (BUT
NOT NECESSARILY LIMITED TO)
REDUCED AIRFLOW DURING
HEATING CAUSING EXCESSIVE
UNDESIRED OPERATION OF THE
MAIN LIMIT CONTROL. FURTHER,
THE MEMORY CARD IS SPECIFIC
TO THE MODEL NUMBER AND
BTU INPUT RATING FOR A SPE-
CIFIC FURNACE AND THIS
INFORMATION SHOULD NOT BE
TRANSPORTED FROM ONE FUR-
NACE (OR COMPONENT) TO
ANOTHER.
49
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