29
EXAMPLE:
Installation’s gas heating (HTG) value: 1,000 BTU/ft
3
(Obtained from gas supplier)
Installation’s seconds per cubic foot: 34 sec/ ft
3
Conversion Factor (hours to seconds): 3600 sec/hr
Input = (Htg. value x 3600) ÷ seconds per cubic foot
Input = (1,000 BTU/ft
3
x 3600 sec/hr) ÷ 34 sec/ ft
3
Input = 106,000 BTU/hr
Minor changes to the input rate may be accomplished through mani-
fold pressure adjustments at the gas valve. Refer to
Section XIV,
Startup Procedure and Adjustment - Gas Manifold Pressure Mea-
surement and Adjustment
for details.
NOTE:
The final manifold
pressure cannot vary by more than ± 0.3” w.c. from the specified
setting. Consult your local gas supplier if additional input rate ad-
justment is required.
5.
Turn ON gas to and relight all other appliances turned off in
step 1. Be certain that all appliances are functioning properly
and that all pilot burners are operating.
T
EMPERATURE
R
ISE
Temperature rise must be within the range specified on the unit rat-
ing 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 Product Data Book 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.
RISE =
SUPPLY
AIR
RETURN
AIR
HEAT EXCHANGER
RADIATION "LINE OF SIG HT"
T
RE TUR N
T
SU PP LY
T
S UP PLY
-
T
RE TURN
Temperature Rise Measurement
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
Section XIV, Startup Procedure and Adjustment -Circulator
Blower Speeds
for speed changing details.
C
IRCULATOR
B
LOWER
S
PEEDS
WARNING
T
O PREVENT PREMATURE FAILURE OF HEAT EXCHANGER, PROPERTY DAMAGE,
PERSONAL INJURY OR DEATH, DO NOT ADJUST THE LIMIT CONTROL (FACTORY
SET).
This furnace is equipped with a multi-speed circulator blower. This
blower provides ease in adjusting blower speeds. The Product Data
Book applicable to your model* provides an airflow table, showing
the relationship between airflow (CFM) and external static pressure
(E.S.P.), for the proper selection of heating and cooling speeds. The
cooling blower speed is shipped set on HIGH, and the heating blower
speed is set as indicated in the Product Data Book applicable to
your model*. These blower speeds should be adjusted by the in-
staller to match the installation requirements so as to provide the
correct heating temperature rise and correct cooling CFM.
To adjust the circulator blower speed, proceed as follows:
1.
Turn OFF power to the furnace.
2.
Select the heating and cooling blower speeds that match the
installation requirements from the
airflow table in the Product
Data Book
.
3.
Relocate desired motor leads to the circulator blower heat
and cool speed terminals on the integrated control module.
(Terminals are identified as HEAT and COOL (hot)). If heating
and cooling blower speeds are the same, a jumper wire must
be used between the heat and cool terminals.
4.
Connect all unused blower motor leads to the “PARK”
terminals on the integrated control module. Any leads not
connected to the “PARK” terminals must be taped.
5.
Turn ON power to furnace.
6.
Verify proper temperature rise as outlined in
Section XIV,
Startup Procedure and Adjustment - Temperature Rise
.
Orange
High
Common/Neutral
Medium Low
Circulator Blower Speeds
Low
Red
Medium Blue
Black
White
XV
XV
XV
XV
XV. NO
. NO
. NO
. NO
. NORM
RM
RM
RM
RMAL SEQUEN
AL SEQUEN
AL SEQUEN
AL SEQUEN
AL SEQUENCE O
CE O
CE O
CE O
CE OF OPERA
F OPERA
F OPERA
F OPERA
F OPERATI
TI
TI
TI
TIO
O
O
O
ON
N
N
N
N
P
OWER
U
P
The normal power up sequence is as follows:
•
115 VAC power applied to furnace.
•
Integrated control module performs internal checks.
•
Integrated control module flashes LED one time.
•
Integrated control module monitors safety circuits
continuously.
•
Furnace awaits call from thermostat.
H
EATING
M
ODE
The normal operational sequence in heating mode is as follows:
•
R and W thermostat contacts close, initiating a call for heat.
•
Integrated control module performs safety circuit checks.
•
Induced draft blower is energized for 15 second prepurge
period causing pressure switch contacts to close. Humidifier
terminals are energized with induced draft blower.
•
Igniter warm up begins after 15 second prepurge expires.
•
Gas valve opens at end of igniter warm up period, delivering
gas to burners and establishing flame.
