# 47904K005
Page 24
Soft Stop
At the end of a cooling or heating cycle, the variable
speed motor will slowly ramp down after a short blower
“off” delay. If continuous blower operation has been
selected, the variable speed motor will slowly ramp down
until it reaches the airflow for that mode.
Passive and Active Dehumidification
Passive Dehumidification
For situations where humidity control is a problem, a
dehumidification feature has been built into the variable
speed motor. At the start of each cooling cycle, the
variable speed motor will run at 82% of the rated airflow
for 7.5 minutes. After 7.5 minutes has elapsed, the motor
will increase to 100% of the rated airflow.
Active Dehumidification
To achieve additional dehumidification, clip the jumper wire
located below the DEHUM terminal on the integrated
ignition/blower control board and connect a humidity control
that opens on humidity rise to the DEHUM and R termi-
nals. The DEHUM terminal on the control board must be
connected to the normally closed contact of the humidity
control so that the board senses an open circuit on high
humidity. In this setup, the variable speed motor will operate
Figure 35
Wiring Connections for Twinning Two G2D93CT/U Furnaces
Two Stage Heating/Single Stage Cooling
at a 18% reduction in the normal cooling airflow rate when
there is a call for dehumidification.
Both the passive and active dehumidification methods
described above can be utilized on the same furnace.
Circulating Airflow Adjustments
Cooling Mode
The units are factory set for the highest airflow for each
model. Adjustments can be made to the cooling airflow by
repositioning the jumper plug marked COOL – A, B, C, D
(see Figure 36) based on the information found in the table.
To determine what CFM the motor is delivering at any time,
count the number of times the amber LED on the control
board flashes. Each flash signifies 100 CFM; count the
flashes and multiply by 100 to determine the actual CFM
delivered (for example: 10 flashes x 100 = 1000 CFM)
.
Heating Mode
The unit as shipped is factory set to run at the middle of
the heating rise range as shown on the unit rating plate. If
higher or lower rise is desired, change the airflow 15% up
or down by moving the ADJUST jumper plug (see Figure
36) from the NORM position to the (+) or (–) position. This
adjustment will also cause the cooling airflow to be raised
or lowered by 15%.
