Rheem RGPE series Installation Instructions Manual page 85

SPECIAL CONFIGURATION –
COMMUNICATING THERMOSTAT
AND FURNACE WITH A NON-
COMMUNICATING CONDENSER
Y Y 1 1 a a n n d d Y Y 2 2 – These terminals may be
used to connect directly to a non-com-
municating condenser when a commu-
nicating thermostat is installed to the
furnace 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" and "Y2" on the I.F.C. are normally
inputs to the furnace control to turn on
the blower when they are energized.
However, in this configuration, these
(normally) inputs become outputs to
energize the condenser when a cooling
call has been sent from the communi-
cating thermostat.
When this configuration is desired, use
the wiring diagram in Figure 52 to con-
FIGURE 52
WIRING DIAGRAM – SPECIAL CONFIGURATION: COMMUNICATING THERMOSTAT AND FURNACE WITH NON-COMMUNICATING CONDENSER
nect the thermostat and condenser to
the furnace control.
For single stage condensers, a jumper
must be installed between Y1 & Y2 at
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 dis-
played within 30 minutes after ener-
gizing the system, communications
can not be established. There are
many reasons why communications
may not be established – including
improper settings of the "TERM" and
"BIAS" switches (see BIAS / TERMI-
NATION) and improper wiring (see
WIRING A FURNACE FOR COM-
MUNICATIONS above).
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