16
Main Burner Flame Check
Flames should be stable, soft and blue (dust may cause
orange tips but they must not be yellow) and extending directly
outward from the burner without curling, floating or lifting off.
Temperature Rise Check
Check the temperature rise through the unit by placing
thermometers in supply and return air registers as close to
the unit as possible. Thermometers must not be able to
sample temperature directly from the unit heat exchangers,
or false readings could be obtained.
1. All registers must be open; all duct dampers must be in
their final (fully or partially open) position and the unit
operated for 15 minutes before taking readings.
2. The temperature rise must be within the range specified
on the rating plate.
NOTE:
Air temperature rise is the temperature difference between
supply and return air.
With a properly designed system, the proper amount of
temperature rise will normally be obtained when the unit is
operated at rated input with the recommended blower speed.
If the correct amount of temperature rise is not obtained, it
may be necessary to change the blower speed. A higher
blower speed will lower the temperature rise. A slower blower
speed will increase the temperature rise.
NOTE:
Blower speed MUST be set to give the correct air tempera-
ture rise through the unit as marked on the rating plate.
External Static Pressure Check
The total external static pressure must be checked on this
unit to determine if the airflow is proper.
Blower Speed Adjustments
WARNING
T
O AVOID PERSONAL INJURY OR DEATH DUE TO ELECTRIC SHOCK, REMOVE
ELECTRICAL POWER FROM THE UNIT BEFORE CHANGING SPEED TAPS ON THE
BLOWER MOTOR.
Refer to the wiring diagram in the appendix to verify speed tap
settings.
All models are equipped with EEM motors. EEM motors are
constant torque motors with very low power consumption.
This motor is energized by 24V. Adjust the CFM for the unit by
changing the 24V low voltage leads to the speed terminal
block on the motor.
Single Stage Models:
Heating-White Lead
Cooling-Yellow Lead
T1 - Low Speed
T4 - Low Speed
T2 - Medium Speed
T5 - High Speed
T3 - High Speed
Two-Stage Models:
Speed
Tap
De fin ition
Lead
C olo r
Spee d
Tap
Def inition
Lead
Color
T1
Low
Speed Heat
White
T3
Low Speed
Coo l
Purple
T2
High
Speed Heat
Bro wn
T4
High Spee d
Coo l
Yellow
T5
High Spee d
Coo l Hi-Sta tic
HEATI NG
COOLING
NOTE:
Heating airflow must be adjusted to provide the tempera-
ture rise shown on rating plate.
Limit Check
Check limit control operation after 15 minutes of operation
by blocking the return air grille(s).
1. After several minutes the main burners must go OFF.
Blower will continue to run.
2. Remove air restrictions and main burners will relight
after a cool down period of a few minutes.
Adjust the thermostat setting below room temperature.
1. Main burners must go OFF.
2. Circulating Air Blower will continue to run for 120, 135 or
150 seconds, (single stage models) or 90, 120, 150, or
180 seconds (two-stage models), depending on the
setting.
1
2
3
10
11
12
9
6
23
6
5
8
9
11
12
L2
L2
L2
L2
D1
L
1
L
1
U
N
U
SED
H
EAT
CO
O
L
FS
K2
K1
R8
R10
R3
K4
K3
R31
LED
1068-83-400A
C27
D3
R38
D9
D10
R34
R35
R4
R11
R42
D12
R36
D11
D14
C20
Z1
R29
R22
C13
R25
D5
D7
Control Board (Single Stage)
LO COOL
HI COOL
LO HEAT
HI HEAT
U6
U7
U4
U5
U3
K2
K1
P1
ECON
STAGE
DELAY
SPEEDUP
SW1
FAULT
RECALL
BLOWER
OFF DELAY
F1
R
C W1 W2 G Y1 Y2
Control Board (Two-Stage)
NOTE:
If necessary, adjust fan OFF delay settings to obtain satis-
factory comfort level.
Unit Shutdown
1. Set the thermostat to lowest setting.
2. Turn off the electrical power supply to the unit.
3. Remove the heat exchanger door on the side of the unit by
removing screws.
4. Move the gas control valve switch to the OFF position. Do
not force.
5. Close manual gas shutoff valve external to the unit.
6. Replace the heat exchanger door on the unit.
7. If cooling and/or air circulation will be desired, turn ON the
electrical power.
