Lennox Elite CBA27UHE Series Manual page 44

L-CBA27UHE with DEHUMIDIFICATION RELAY K183
Operation Sequence
1-. If there is no dehumidification demand when 24 volts is
applied to the system, the thermostat will send 24 volts
to the K183 dehumidification relay coil. The normally‐
open relay contacts 5 and 9 will close and contacts 1
and 9 will open.
2-. If the total system static is higher than 0.49 in. w.g., a
higher indoor blower speed may be needed to satisfy
supply air requirements.
3-. The lower the indoor blower speed during dehumidifi­
cation demands, without freezing the indoor coil, the
better moisture removal will be. In Humiditrol
tions, this lower speed will increase the temperature
rise on the Humiditrol
4-. When more than one motor tap is energized, built in
logic gives the highest speed tap precedence.
5-. On a dehumidification call, the thermostat will remove
24 volt output from the "D" terminal; the "Y2" terminal
(if available) becomes activated with 24 volts. This will
de-energize K183 dehumidification relay and output 24
volts from Y2.
NOTE - For any of the following configurations, refer to
figure wiring diagram for proper system indoor blower
fan speed tap selection.
Single Stage Systems
Y1 cooling demand from the room thermostat with no
dehumidification demand—24 volts passes to the Y1 ter­
minal on the coil blower. The factory jumper from Y1 and Y2
will direct the 24 volt signal through the closed set of con­
tacts to the selected indoor blower cooling speed (factory
set on Tap # 3 - white wire). Systems with total system stat­
ics between 0.50 and 0.80 in. w.g. may require a motor
speed change.
Y1 cooling demand with dehumidification demand—
K183 relay de-energizes. Contacts 5 and 9 open and iso­
late the cooling tap speed on the motor from the system.
The room thermostat will still be calling for a Y1 demand, so
24 volts will still output from the Y1 and G terminals. The Y1
signal (factory jumpered to Y2 on the indoor unit's 24 volt
terminal strip) will be isolated from the indoor blower motor
by the opening of contacts 5 to 9 but the G signal will still be
able to provide 24 volt power to the continuous indoor blow­
er speed (factory set on Tap # 1 - green wire). Systems with
total system statics between 0.50 and 0.80 in. w.g. may re­
quire a motor speed change.
Two Stage Systems
NOTE - Factory jumper wire between Y1 and Y2 on the in­
door unit 24 volt terminal strip must be removed for two‐
stage systems.
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coil.
Y1 cooling demand from the room thermostat with no
dehumidification demand—24 volts passes to the Y1 ter­
minal on the coil blower. The Y1 demand will be isolated
from the cooling tap speed on the indoor blower motor by
removal of the jumper between Y1 and Y2 on the indoor
unit's terminal strip on systems where the total system stat­
ic is less than 0.50 in. w.g. The room thermostat outputs Y1
and G on a Y1 demand. The G signal from the room thermo­
stat will still provide 24 volt power to the continuous indoor
blower speed (factory set on Tap # 1 - green wire).
Systems with total system statics between 0.50 and 0.80 in.
w.g. will require the yellow wires from the K183 relay termi­
applica­
nal 1 to be connected to Y1 on the unit's indoor terminal strip
and Tap # 2 (yellow from the indoor blower motor). The Y1
input from the indoor unit will allow the indoor blower motor
to run on Tap # 2 - yellow wire.
The G signal from the room thermostat will still provide 24
volt power to the continuous indoor blower speed (factory
set on Tap # 1 - green wire).
Y2 cooling demand from the room thermostat with no
dehumidification demand—24 volts passes to the Y2 ter­
minal on the coil blower. The Y2 demand will pass through
closed relay contacts 5 and 9 to the selected indoor blower
cooling speed (factory set on Tap # 3 - white wire). Systems
with total system statics between 0.50 and 0.80 in. w.g. may
require a motor speed change.
Y1 or Y1/Y2 cooling demand with dehumidification de­
mand—K183 relay de-energizes and the room thermostat
Y2 energizes. K183 relay contacts 5 and 9 will open and
isolate the cooling blower speed on the motor from the sys­
tem. The room thermostat will still be calling for a Y1, Y2,
and G demand, so 24 volts will still be output to the terminal
strip in the indoor coil blower. Y1 is not wired to the K183
relay, Y2 will send 24 volts through the K183 relay 9 to1
closed contacts to the yellow wire that is not connected to
the motor in systems where the total system static is less
than 0.50 in. w.g. The G signal will still provide 24 volt power
to motor Tap # 1 - Green wire. Indoor blower motor will run
on Tap # 1 - Green wire. Systems with total system statics
between 0.50 and 0.80 in. w.g. may require a motor speed
change.
Systems with total system statics between 0.50 and 0.80 in.
w.g. will require the yellow wires from the K183 relay termi­
nal 1 to be connected to Y1 on the unit's indoor terminal strip
and Tap # 2 - yellow from the indoor blower motor. The Y1
input from the indoor unit will allow the indoor blower motor
to run on Tap # 2 - Yellow wire. The Y2 demand will go
through K183 relay contacts 9 to 1 to indoor blower motor
speed Tap # 2 - Yellow wire. The G signal will still provide 24
volt power to motor Tap # 1 - Green wire. The indoor blower
motor will run on Tap # 2 - Yellow wire.
Page 44