44
the call is for high heat, the gas valve and induced
draft blower will change to high stage.
•
Circulator blower is energized on heat speed following
a thirty (30) second blower on delay. The circulator
blower requires thirty seconds to ramp up to full
speed. Electronic air cleaner terminal is energized
with circulator blower.
•
Furnace is now operating on the specified stage
called for by the two-stage thermostat.
•
Furnace runs, integrated control module monitors
safety circuits continuously.
•
If the two-stage thermostat changes the call from
low heat to high heat, the integrated control module
will immediately switch the induced draft blower,
gas valve, and circulator blower to their high stage
settings.
•
If the two-stage thermostat changes the call from
high heat to low heat, the control will immediately
switch the induced draft blower and gas valve to
their low stage settings. The circulator blower will
LED
Description
Off
Normal condition
Red
Communications
LED
1 Flash
Communications
Failure
2 Flashes Out-of-box reset
Green Receive
LED
Off •Nopower
•Communications
error
1 Steady
Flash
No network
found
Rapid
Flashing
Normal network
traffc
On Solid Data 1/ Data 2
miss-wire
Possible Cause
Corrective Action
Comments
None
None None
Communications
Failure
•Depress Learn Button
•Verify that bus BIAS and
TERM dipswitches are in
the ON position.
•Depress once quickly for
a power-up reset
•Depress and hold for 2
seconds for an out-of-box
reset
•Control power up
•Learn button depressed
None
None
•No power to furnace
•Open fuse
•Communications error
•Check fuses and circuit
breakers; replace/reset
•Replace blown fuse
•Check for shorts in low
voltage wiring in furnace/
system
•Reset network by
depressing learn button
•Check data 1/ data 2
voltages
•Turn power OFF prior to
repair
•Broken/ disconnected
data wire(s)
•Furnace is installed
as a legacy/ traditional
system
•Check communications
wiring (data 1/ data 2
wires)
•Check wire connections
at terminal block
•Verify furnace installation
type (legacy/ traditional
or communicating) Check
data 1/ data 2 voltages
•Turn power OFF prior to
repair
•Verify wires at terminal
blocks are securely
twisted together prior to
inserting into terminal
block
•Verify data1 and data
voltages as described
above
Control is “talking” on
network as expected
None
None
•Data 1 and data 2 wires
reversed at furnace,
thermostat, or CT™
compatible outdoor AC/
HP
•Short between data 1
and data 2 wires
•Short between data 1
or data 2 wires and R
(24VAC) or C (24VAC
common)
•Check communications
wiring (data 1/ data 2
wires)
•Check wire connections
at terminal block
•Check data 1/ data 2
voltages
•Turn power OFF prior to
repair
•Verify wires at terminal
blocks are securely
twisted together prior to
inserting into terminal
block
•Verify data1 and data
voltages as described
above
remain on high heating speed for thirty (30) seconds
before switching to the low heat circulating speed.
•
R and W1 (or R and W1/W2) thermostat contacts
open, completing the call for heat.
•
Gas valve closes, extinguishing flame.
•
Induced draft blower is de-energized following a
fifteen second post purge. Humidifier terminals are
de-energized.
•
Circulator blower continues running for the selected
heat off delay period (90, 120, 150 or 180 seconds).
The speed run during this period depends on the
last heat call provided by the thermostat.
If the last call for heat was a call for low heat, the
air circulator motor will run on low heat speed for
the duration of the heat off delay period (90, 120,
150 or 180 seconds).
If the last call for heat was a call for high heat, the
air circulating motor will run on the high heating
speed for thirty (30) seconds and then switch to the
low heating speed for the
balance
of the heat off
delay period (60, 90, 120 or 150 seconds).
