5.1st and 2nd Stage called simultaneously
•The 1st stage call is processed as described in paragraph 1 above.
•Once Flame Rectification is established, 2nd Stage is entered immediately as described in paragraph 2 above.
6.1st and 2nd Stage satisfied simultaneously
•Both stages of the Gas Valve are
•Flame Rectification is lost.
•The Inducer and Hum relays are
•30 seconds later the Control shifts the Blower from Heat High to Heat Low.
•After the
7.Manual Fan Operation
•With the thermostat in the Fan On position, a circuit is completed between R and G of the Control.
•The Heat Low and EAC relays are energized by the Control.
8.Call for Cooling
•The thermostat closes two circuits R to Y and R to G. Since the Outdoor Unit is connected to Y and C at the Control, it is ener- gized.
•The Cool and EAC relays are energized by the Control.
•A
9.Cooling call satisfied
•The thermostat opens the R to Y and R to G circuits.
•The Outdoor Unit is
•The
•After 60 seconds, the Cool and EAC relays are
10.
•The wall thermostat will energize the Y1 circuit for low cooling and the Y2 circuit for high cooling.
CONTROL BOARD
Variable speed motors will adjust the motor speed in order to maintain the indoor fan CFM. The control board is used to control the blower speed thus the CFM when the unit is operating in the heating or cooling modes. The blower CFM for cooling can be modified by changing the jumper pin position on the taps selection marked COOL and ADJ.
The blower CFM for heating can be modified by changing the jumper pin position on the taps selection marked HEAT. The taps selection pins have been preset at the factory to provide the maximum CFM. “Air Flow Data” table in the installation manual list the recommended jumper pin settings.
If a lesser CFM is required for a specific HVAC system the taps selec- tion pins can be moved to the "B", "C", or "D" positions. Pin "A" will pro- vide the highest CFM and "D" will provide the lowest CFM. The taps selection marked DELAY are used for cooling only. The recommended settings for these jumper pins are listed in Delay taps selection.
HEATING AIRFLOW
The heating airflow has been preset at the factory to provide maximum CFM. If a lesser CFM is required for a specific HVAC system the “JUMPER” on the HEAT selection pins on the control board may be moved to tap “B”, “C”, or “D”.
HEAT Taps Selection on the control board. Pin Position A: will provide the highest CFM.
Pin Position B and C: are the medium and medium low CFM settings.
Pin Position D: will provide the lowest CFM.
Refer to “Air Flow Data” table in the installation manual for the proper “HEAT” Taps Selection for the model furnace you are installing.
NOTE: When changing jumper positions, make sure that the jumper is pushed all the way on the pins. If the jumper is not making good contact or is left off completely, the blower will operate as if the jumper were in the “A” position.
NOTE: Power to the blower must be removed for at least 4 seconds after a heat or cool tap selection change, in order for the motor to recog- nize an adjustment. The fixed blower on delay and adjustable
ADJUSTMENT OF FAN CONTROL SETTINGS
Heating Indoor Fan Off Delay
Changing the blower delay jumper on the Furnace Control Board can change the indoor fan “OFF” time delay. Refer to Figure 6 for the jumper settings to obtain the desired fan OFF delay. The blower off delay must be long enough to adequately cool the furnace, but not so long that cold air is blown into the living space.
The blower on delay is fixed at 30 seconds and cannot be adjusted.
| HEAT | HI HEAT | CONTINUOUS | BLOWER | |
DEHUMIDISTAT | FAN SPEED | ||||
DELAY | |||||
JUMPER | DELAY | JUMPER | OFF DELAY | ||
JUMPER | |||||
| JUMPER |
| JUMPER | ||
|
|
|
LOW
VOLTAGE
TERMINALS
COOLING
PROFILE
JUMPER
BLOWER
SPEED
JUMPERS
FIGURE 6: Furnace Control Board
6 | Unitary Products Group |
