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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.
HEAT EXCHANGER
RADIATION "LINE OF SIGHT"
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
B
S
IRCULATOR
LOWER
PEEDS
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, show-
ing the relationship between airflow (CFM) and external static pres-
sure (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 appli-
cable to your model.
These blower speeds should be adjusted by
the installer 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 LO HEAT-H, HI HEAT-H and
COOL-H (hot)). If a heating speed and the cooling blower
speed 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.
SUPPLY
AIR
T
SUPPLY
T
T
RISE =
-
SUPPLY
RE TURN
T
RETURN
RETURN
AIR
WARNING
5. Turn ON power to furnace.
6. Verify proper temperature rise as outlined in Section XIV,
Startup Procedure and Adjustment - Temperature Rise.
Circulator Blower Speeds
Low
Medium Low
Medium
High
Common/Neutral
XV. NORMAL SEQUENCE OF OPERATION
P
U
OWER
P
The normal power up sequence is as follows:
•
115 VAC power applied to furnace.
•
Integrated control module performs internal checks.
•
Integrated control module LED will light.
•
Integrated control module monitors safety circuits
continuously.
•
Furnace awaits call from thermostat.
H
M
EATING
ODE
(M
DIP
ODE
SWITCH IS SET TO
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.
•
Igniter warm up begins after 15 second prepurge expires.
•
Low and high stage gas valves open at end of igniter warm
up period, delivering gas to burners and establishing flame.
•
Integrated control module monitors flame presence. Gas
valve will remain open only if flame is detected.
•
Circulator blower is energized on high heat speed following
a fixed thirty second blower on delay. Electronic air cleaner
terminals are energized with circulator blower.
•
Furnace operates; integrated control module monitors
safety circuits continuously.
•
R and W thermostat contacts open, completing the call for
heat.
•
Gas valve closes, extinguishing flame.
•
Induced draft blower is de-energized following a fifteen
second post purge.
•
The circulator blower remains at high heat speed for thirty
seconds. The circulator blower then switches to low heat
speed for the remainder of the selected heat off delay period.
For example, the selected heat off delay period is 150
seconds. The circulator blower operates at high heat for 30
seconds and at low speed for 150 - 30 = 120 seconds.
•
Furnace awaits the next call from thermostat.
29
Red
Orange
Blue
Black
White
"1 STG"
)
POSITION
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