Grounding; Twinning - Nordyne 80+ AFUE *SA Installation Instructions Manual

IMPORTANT NOTE: Set the heat anticipator according
to the instructions supplied by the thermostat
manufacturer.
To determine the heat anticipator setting:
1. Add the current draw of the system components; or
2. Measure the current fl ow on the thermostat R-W circuit
after the circulating blower motor has started.
A/C CONDENSING UNIT
3 AMP
ROOM
FUSE
THERMOSTAT
R
Connect
C
R & W
Y
For Heating
G
Only
W
9 6 3
NOTE: The "Y" terminal 8 5
4 1
7
on the control board
must be connected to the
thermostat for proper
6 3
2
cooling mode operation. 5
4 1
FIELD WIRING
LOW VOLTAGE
CONNECTION
NEUTRAL LEADS
Figure 14. Low Voltage Field, Four-wire
Heating/Cooling Applications

Grounding

WARNING:
To minimize personal injury, the furnace cabinet
must have an uninterrupted or unbroken electrical
ground. The controls used in this furnace require
an earth ground to operate properly. Acceptable
methods include electrical wire or conduit
approved for ground service. Do not use gas
piping as an electrical ground!
CONDENSING UNIT
CONTROL BOX
EXPANSION PORT
(MOTOR CONNECTION)
SPEED
SELECT
STATUS
RED
GREEN
FLAME
YELLOW
180
BLOWER
2 120
OFF
90
DELAY
60
MOTOR SPEED TAPS
(NOT USED)
ELECTRONIC AIR CLEANER
HUMIDIFIER TAP

Twinning

Single stage G7 furnaces are not supplied with a built-
in twinning capability. Other valuable features and
enhancements were made to the new control that made it
necessary to remove the twinning capability. All standard
two-stage furnaces equipped with the fi xed speed iSEER™
motor include a twinning terminal on the blower control
board.
However, if both single stage G7 furnaces are upgraded
to the fi xed speed iSEER ™ blower, the twin terminal on
the blower control boards (Figure 15) may be used to
twin the single stage furnaces only if the following criteria
are met:
• Both furnaces and motors must be the same size.
• Both motors must be on the same speed for cooling
and heating.
• Both furnaces must have a common return duct and
common supply plenum.
• Both furnaces must be on the same leg of power.
IMPORTANT NOTE: G7 furnaces equipped with
variable speed iSEER ™ motors may not be twinned
under any circumstances.
Please contact your furnace distributor for technical
details.
THERMOSTAT
W G Y R
R
C
Y
G
W
FURNACE
BOARD
BOARD
TWIN TERMINAL
A/C
UNIT
FURNACE 1
Figure 15. Single Stage Twinning
R
C
Y
G
W
FURNACE
BOARD
FSHE FSHE
BOARD
TWIN TERMINAL
FURNACE 2
19