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 terminals. 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 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 32) 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 theADJUSTjumper plug (see Figure 32) from the NORM position to the (+) or
The TEST position on the ADJUST tap is not used.
The jumper plug on the HEAT tap should remain in the position (A, B, C, or D) listed in the HEAT Setting column in the table found in Figure 32. Changing the setpoints may not increase or decrease heating blower speeds. In some cases, running the blower with the heat settings in the wrong position may cause the furnace to operate outside the furnace’s intended temperature rise range.
Continuous Blower Operation
The comfort level of the living space can be enhanced when using this feature by allowing continuous circulation of air between calls for cooling or heating. The circulation of air occurs at half the full cooling airflow rate.
To engage the continuous blower operation, place the fan switch on the thermostat into the ON position. A call for fan from the thermostat closes R to G on the ignition control board. The control waits for a 1 second thermostat debounce delay before responding to the call for fan by ramping the circulating blower up to 50% of the cooling speed. When the call for continuous fan is satisfied, the control immediately ramps down the circulating blower.
ADJUST, HEAT, and COOL Taps
on Integrated Ignition/Blower
Control Board
Figure 32
Page 28 of 41 | Issue 1034 |
