GAMA Gas-Fired Furnace, User'S Information Manual

CONTROL BOARD & VARIABLE SPEED MOTOR FEATURES

Humidifier  Connections:

Terminals are provided on the blower control board for
connections to a 120-volt optional humidifier. The "HUM"
terminal is energized whenever the thermostat calls for
heat. Refer to furnace wiring diagram for specific
connection information.

Electronic  Air  Cleaner  Connections:

Terminals are provided on the blower control board for
connection of a 120-volt optional electronic air cleaner.
The "EAC" terminal is energized whenever the thermostat
calls for heat, cooling, or continuous blower. Refer to the
furnace wiring diagram for specific connection information.

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 de-energizes the
circulating blower.

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. If this feature
is not desired, clip the jumper wire between Y and O on
the integrated ignition/blower control board. With Y and
O not jumpered, the variable speed motor will reach
100% of the rated airflow within 10 seconds of a call for
cooling.

Additional dehumidification can be achieved by
connecting a humidistat to the DEHUM and R terminals
on the integrated ignition/blower control board. In this
setup, the variable speed motor will operate at a 10%
reduction in the normal cooling airflow rate when there is
a call for dehumidification.

Both dehumidification methods described above can be
utilized on the same furnace.

Variable  Speed  Features:

The furnace is equipped with a variable speed circulation
air blower motor that will deliver a constant airflow within
a wide range of external static pressures.

Other features of this variable speed motor include:

Soft  Start:

The variable speed motor will slowly ramp up to normal
operating speed. This minimizes noise and increases
comfort by eliminating the initial blasts of air encountered
with standard motors.

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.

Circulating Airflow Adjustments

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.

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 AirFlow Adjustment Table on page 4) based on
the information found in the table.

By moving the ADJUST jumper plug (see Table on page
4) from the NORM position to the (+) or (-) position will
also cause the cooling airflow setting to be raised or
lowered by 15%.

The TEST position on the ADJUST tap is not used.

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).

20558801

Issue 0442

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