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G-Power Exhaust Fan
The power exhaust fan (PEF) requires the use of a gravity
exhaust damper and economizer and is used in downflow
applications only. See figure 32. The PEF provides exhaust
air pressure relief and also runs when return air dampers
are closed and the supply air blower is operating. See in
stallation instructions for more detail.
FIGURE 32
GED AND PEF INSTALLATION
PEF POWER
EXHAUST FAN ASSEMBLY
(ORDERED SEPARATELY)
GED GRAVITY
EXHAUST
P18
DAMPERS
Power Exhaust Setpoint Adjustment
Locate the A6 enthalpy control in the control area. The EXH
SET potentiometer is factory-set at approximately 50% of
the dial range. See figure 33. Power exhaust fans will be en
ergized 30 seconds after dampers are 50% open. Adjust the
EXH SET potentiometer higher (clockwise toward 10V) to
energize fans when dampers are further open. Adjust the
EXH SET potentiometer lower (counterclockwise toward
2V) to energize fans when dampers are further closed. (Thir
ty-second delay allows dampers to partially open before ex
haust fan starts.)
H-Optional Cold Weather Kit (Canada only)
Electric heater is available to automatically control the
minimum temperature in the gas burner compartment.
Heater is ETL/CSA certified to allow cold weather opera
tion of unit down to ‐60° F (‐50° C ).
The kit includes the following parts:
1- Transformer (T20) is a 600V to 120/240V step-down trans
former mounted in the blower compartment.
2- T20 has two in line fuses (F20), one on each leg of the trans
former. Both are rated at 15 amps.
3- The strip heater (HR6) is located as close as possible to the
gas valve. It is wired in series with T20. The strip heater is
rated at 500 Watts
4- A thermostat mounting box is installed on the
vestibule of the heating compartment. Included in the
box are the following thermostat switches:
FIGURE 33
A6 ENTHALPY CONTROLLER
A
B
C
D
Open
Min
Pos
Free
Cool
DCV
EXH
EXH
Set
2V 10V
DCV
Max
2V 10V
DCV
Set
2V 10V
ADJUST POWER
EXHAUST FAN
SETPOINT
ENERGIZED WHEN
DAMPER POSITION
IS HIGHER THAN
EXHAUST FAN
SETPOINT
a - Thermostat switch (S59) is an auto‐reset SPST N.C.
switch which opens on a temperature drop. The
switch is wired in series with 24V power and the com
bustion air blower switch. When the temperature
drops below ‐30° F (-35° C) the switch opens and the
gas heat section is de‐energized. The switch automati
cally resets when the heating compartment tempera
ture reaches -10° F (-12° C).
b - Thermostat switch (S60) is an auto‐reset SPST
N.C. switch which opens on a temperature rise.
The switch is wired in series with HR6 and T20.
When the temperature rises above 20° F (‐7° C) the
switch opens and the electric heater is de‐energized.
The switch automatically resets when the heating
compartment temperature reaches ‐10° F (23.3° C).
c -Thermostat switch (S61) is an auto‐reset SPST
N.O. switch which closes on a temperature drop.
The switch is wired in series with HR6 and T20.
When temperature drops below 20° F (‐7° C) the
switch closes and electric heater is energized.
The switch automatically opens when heating
compartment temperature reaches 76° F (24° C).
I-Control Systems
Three different types of control systems may be used with
the KGA series units. All thermostat wiring is connected to
TB1 located in the control area. Each thermostat has addi
tional control options available. See thermostat installation
instructions for more detail.
1- Electro‐mechanical thermostat (13F06)
The electro‐mechanical thermostat is a two stage heat /
two stage cool thermostat with dual temperature levers.
A non‐switching or manual system switch subbase
may be used.
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