SYSTEM OPERATION
21
Using A Leak Detection
10.00
Measuring Inlet Gas Pressure (Alt. Method)
Manifold Gas Pressure
Gas
Range
Nominal
Natural
Low Stage
1.6 - 2.2” w.c.
1.9” w.c.
High Stage
3.2 - 3.8” w.c.
3.5” w.c.
Propane
Low Stage
5.7 - 6.3” w.c.
6.0” w.c.
High Stage
9.7 - 10.3” w.c. 10.0” w.c.
Temperature Rise
Temperature rise must be within the range specified on the
unit rating plate. An incorrect temperature rise may result
in condensing in or overheating of the heat exchanger.
An airflow and temperature rise table is provided in the
Specification Sheet applicable to your model. Determine
and adjust temperature rise as follows:
1.
Operate furnace with burners firing for approximately
ten minutes. Ensure all registers are open and all duct
dampers are in their final (fully or partially open) position.
2. Place thermometers in the return and supply ducts as
close to the furnace as possible. Thermometers must
not be influenced by radiant heat by being able to “see”
the heat exchanger.
3. Subtract the return air temperature from the supply air
temperature to determine the air temperature rise. Allow
adequate time for thermometer readings to stabilize.
4. Adjust temperature rise by adjusting the circulator blower
speed. Increase blower speed to reduce temperature
rise. Decrease blower speed to increase temperature
rise. Refer to
Startup Procedure and Adjustment
-Circulator Blower Speeds
for speed changing details.
SUPPLY
AIR
RETURN
AIR
Temperature Rise Measurement
Diagnostics
Accessing the furnace’s diagnostic menu provides access
to the last six faults detected by the furnace. Faults are
stored most recent to least recent, Any consecutively
repeated fault is stored a maximum of three times.
Example: A clogged return air filter causes the furnace limit
to trip repeatedly. The control will only store this fault the
first three consecutive times the fault occurs. Navigate to
the diagnostics menu as described above in the thermostat
installation manual.
NOTE: It is highly recommended that the fault
history be cleared when performing maintenance
or servicing the furnace.
NORMAL SEQUENCE OF OPERATION
Power Up
The normal power up sequence is as follows:
•
115 VAC power applied to furnace.
•
Integrated control module performs internal checks.
•
Integrated control module monitors safety circuits
continuously.
•
Furnace awaits call from thermostat. 7-segment LED’s
display
Id L
while awaiting call from thermostat.
Heating Mode
The normal operational sequence in heating mode is
as follows:
•
W thermostat contact closes, initiating a call for heat.
