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14. Close thermostat contacts to provide a call for heat.
15. Retest for leaks. If bubbles form, SHUT OFF GAS AND
REPAIR ALL LEAKS IMMEDIATELY!
Input (Natural Gas Only) Check
Gas
BTU
To measure the gas input use a gas meter and proceed as
follows:
1. Turn off gas supply to all other appliances except the unit.
2. With the unit operating, time the smallest dial on the meter
for one complete revolution. If this is a 2 cubic foot dial,
divide the seconds by 2; if it is a 1 cubic foot dial, use the
seconds as is. This gives the seconds per cubic foot of gas
being delivered to the unit.
3. INPUT=GAS HTG VALUE x 3600 / SEC. PER CUBIC FOOT
Example: Natural gas with a heating value of 1000 BTU per cubic
foot and 34 seconds per cubic foot as determined by Step 2, then:
Input = 1000 x 3600 / 34 = 106,000 BTU per Hour. NOTE:
BTU content of the gas should be obtained from the gas
supplier. This measured input must not be greater than
shown on the unit rating plate.
4. Relight all other appliances turned off in step 1. Be sure all
pilot burners are operating.
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.
Checking Temperature Rise
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 temperature
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.
Total External Static Testing
1. Using a digital manometer measure the static pressure of
the return duct at the inlet of the unit (Negative Pressure).
2. Measure the static pressure of the
Measure).
3. Add the two readings together.
NOTE: Both readings may be taken simultaneously and read directly
on the manometer if so desired.
4. Consult proper table for quantity of air. If the external static
pressure exceeds the minimum or maximum allowable
statics. Check for closed dampers, dirty filters, undersized
or poorly laid out ductwork.
Blower Speed Adjustments
O AVOID PERSONAL I NJURY OR D EATH DUE T O ELECTRIC S HOCK, R EMOVE
T
ELECTRICAL P OWER F ROM THE UNIT BEFORE C HANGING SPEED TAPS O N THE
BLOWER M OTOR.
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
T1 - Low Speed
T2 - Medium Speed
T3 - High Speed
Two-Stage Models:
HEATING
Speed
Definition
Tap
Low
T1
Speed Heat
High
T2
Speed Heat
NOTE: Heating airflow must be adjusted to provide the temperature rise
shown on rating plate.
16
supply duct (Positive
WARNING
Cooling-Yellow Lead
T4 - Low Speed
T5 - High Speed
COOLING
Lead
Speed
Definition
Color
Tap
Low Speed
White
T3
Cool
High Speed
Brown
T4
Cool
High Speed
T5
Cool Hi-Static
Lead
Color
Purple
Yellow
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