Rheem RGFG Installation Instructions Manual page 107

SPECIAL CONFIGURATION
– COMMUNICATING THER-
MOSTAT AND FURNACE
WITH A NON-COMMUNI-
CATING CONDENSER
Y1 and Y2 – This terminal may be used
to connect directly to a non-communi-
cating condenser when a communicat-
ing thermostat is installed to the fur-
nace but a non-communicating con-
denser is installed in the system. While
the optimum configuration is with a
communicating condenser connected to
the network, there may be installations
where this is not desired. In these
cases, the thermostat will be communi-
cating with the furnace control and the
furnace control will energize the con-
denser as necessary (the additional
relays have been added to the furnace
control to allow this operation).
The thermostat connections labeled
"Y1" on the I.F.C. is normally an input
to the furnace control to turn on the
blower when energized. However, in
this configuration, this (normally) input
becomes an output to energize the
condenser when a cooling call has
been sent from the communicating ther-
mostat.
When this configuration is desired, use
the wiring diagram in Figure 64 to con-
FIGURE 64
WIRING DIAGRAM – SPECIAL CONFIGURATION: COMMUNICATING THERMOSTAT AND FURNACE WITH NON-COMMUNICATING CONDENSER
ST-A1173-01
nect the thermostat and condenser to
the furnace control.
NOTE: A heat pump condenser cannot
be installed with this configuration.
There is no control for the reversing
valve.
STARTUP FOR SYSTEMS CONFIG-
URED WITH COMMUNICATIONS
WARNING
INSTALLATION OF LINE VOLTAGE
AND GAS MUST BE PERFORMED
ACCORDING TO INSTRUCTIONS
WRITTEN IN THIS MANUAL. FAIL-
URE TO DO SO COULD RESULT IN
INJURY OR DEATH.
When the furnace is configured for
communications, the components on
the network (i.e. furnace, thermostat
and condenser) must establish commu-
nications before engaging a heat (or
other) thermostat demand. The proce-
dure for establishing communications is
automatic and is described below.
Once communications is established,
the start-up procedure will be the same
as the general start-up instructions
described in the section of this manual
titled START-UP PROCEDURES.
Once the communicating wiring is
properly installed and the furnace is
connected to line voltage, the sys-
tem can be turned on. The thermo-
stat will display the following text:
SEARCHING
is displayed several times for sever-
al seconds. Next, the text
FURNACE FOUND
and
AIR CONDITIONER FOUND
or
HEAT PUMP FOUND
(depending on which is installed in
the system) will be displayed. The
process can take several minutes
(up to a maximum of 30) to com-
plete. If these messages are not
displayed within 30 minutes after
energizing the system, communica-
tions can not be established. There
are many reasons why communica-
tions may not be established –
including improper settings of the
"TERM" and "BIAS" switches (see
BIAS / TERMINATION) and improp-
er wiring (see WIRING A FURNACE
FOR COMMUNICATIONS above).
NOTE:
DEHUMIDIFICATION FUNCTION FROM A COMMUNICAT-
ING THERMOSTAT WILL NOT BE POSSIBLE WITH THIS
CONFIGURATION.
107