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1. Determine the tonnage of the cooling system installed with
the furnace. If the cooling capacity is in BTU/hr divide it by
12,000 to convert capacity to tons.
Example: Cooling Capacity of 30,000 BTU/hr.
30,000/12,000 = 2.5 Tons
2. Determine the proper air flow for the cooling system.
Most cooling systems are designed to work with air
volume between 350 and 450 CFM per ton. Most
manufacturers recommend an air flow of about 400
CFM per ton.
Example: 2.5 tons X 400 CFM per ton = 1000 CFM
3. Select the heating speed for your model from the
heating speed chart in the Specification Sheet. The
selected speed must provide a temperature rise within
the rise range listed with the particular model.
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 9 on page
34, or in the Specification Sheet.
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).
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 the
Temperature Rise section of Startup Procedure and
Adjustment.
In general lower heating speeds will: reduce electrical consump-
tion, lower operating sound levels of the blower, and increase
the outlet air temperature delivered to the home. The speeds
available allow the blower performance to be optimized for the
particular homeowner's needs.
Blower Heat Off Delay Timings
The delay is factory shipped at 150 seconds but may be
changed to suit the installation requirements and/or home-
owner preference.
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.
•
LED will flash once at power up then remain on.
•
Integrated control module monitors safety circuits
continuously.
•
Furnace awaits call from thermostat.
Heating Mode
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 30 second
pre-purge period causing pressure switch contacts
to close.
•
Igniter warm up begins after 15 second pre-purge
expires.
•
Gas valve opens at the 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 five 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
thirty second post purge.
•
HUM terminal is de-energized.
•
Circulator blower continues running for the selected
heat off delay period. Factory set at 150 seconds.
If required this can be changed in the field.
•
EAC terminal is de-energized
•
Furnace awaits next call from thermostat.
Cooling Mode
The normal operational sequence in cooling mode is as follows:
•
R,Y and G thermostat contacts close, initiating a call
for cool.
•
Integrated control module performs safety circuit
checks.
•
Outdoor fan and compressor are energized.
•
Circulator blower is energized on the cool speed.
Following a fixed 6 second delay. Other timing
available is 45 seconds. Jumper settings on the
integrated control board is B for 45 seconds delay.
•
EAC terminal is energized.
•
Furnace circulator blower and outdoor cooling unit
run their appropriate speeds, integrated control
module monitors safety circuits continuously.
•
R,Y and G thermostat contacts open, completing
the call for cool.
•
Outdoor fan and compressor are de-energized.
•
Circulator blower continues running during a cool
off delay period of 45 seconds. EAC terminals are
denergized.
•
Furnace awaits next call from thermostat.
28
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