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Other Unit Adjustments
Primary Limit
The primary limit is located on the heating compartment
vestibule panel. This limit is factory set and requires no
adjustment.
Flame Rollout Switches (Two)
These manually reset switches are located on the front of
the burner box. These limits are factory set and require no
adjustment.
Pressure Switch
The pressure switch is located in the heating compartment
on the cold end header box. This switch checks for proper
combustion air inducer operation before allowing ignition
trial. The switch is factory set and must not be adjusted.
Temperature Rise
After the furnace has been started and supply and return
air temperatures have been allowed to stabilize, check
the temperature rise. If necessary, adjust the blower
speed to maintain the temperature rise within the range
shown on the unit nameplate. See Table 16 for allowable
heating speeds. Increase the blower speed to decrease
the temperature. Decrease the blower speed to increase
the temperature rise. Failure to adjust the temperature rise
may cause erratic limit operation.
Fan Control
The fan ON time of 30 seconds is not adjustable. The fan
OFF delay (amount of time that the blower operates after
the heat demand has been satisfied) may be adjusted
by changing the jumper position across the five pins on
the integrated control. The unit is shipped with a factory
heat fan OFF setting of 90 seconds. The fan OFF delay
affects comfort and is adjustable to satisfy individual
applications. Adjust the fan OFF delay to achieve a supply
air temperature between 90° and 110° F at the moment
that the blower is de-energized. Longer OFF delay settings
provide lower return air temperatures; shorter settings
provide higher return air temperatures. See Figure 60.
Constant Torque Motor
These units are equipped with a constant torque ECM
motor. It has a DC motor coupled to an electronic control
module,both contained in the same motor housing. The
motor is programmed to provide constant torque at each of
the five selectable speeds. The motor has five speed taps.
Each tap requires 24 volts to energize.
Thermostat Heat Anticipation
Set the heat anticipator setting (if adjustable) according to
the amp draw listed on the wiring diagram that is attached
to the unit.
Page 42 of 53
To adjust fan−o timing, reposition jumper across pins to
60 Second
o Time
Figure 60. Heat Fan-OFF Time in Seconds
Electrical
1.
Check all wiring for loose connections.
2.
Check for the correct voltage at the furnace (with
furnace operating). Correct voltage is 120 VAC ± 10%.
3.
Check amp–draw on the blower motor with the blower
compartment access panel in place.
Motor Nameplate____________ Actual____________
Blower Speeds
Follow the steps below to change the blower speeds.
1. Turn off electrical power to furnace.
2.
Remove blower compartment access panel.
3.
Disconnect existing speed tap at control board speed
terminal.
NOTE: Termination of any unused motor leads must
be insulated.
4.
Place unused blower speed tap on integrated control
"PARK" terminal or insulate.
5.
Refer to blower speed selection chart on unit wiring
diagram for desired heating or cooling speed. See
Blower performance data beginning on the next page.
See Table 16 for allowable heating speeds.
6.
Connect selected speed tap at control board speed
terminal.
7.
Re-secure blower access panel.
8.
Turn on electrical power to furnace.
9.
Recheck temperature rise.
Electronic Ignition
The integrated control has an added feature of an internal
Watchguard control. The feature serves as an automatic
reset device for integrated control lockout caused by
ignition failure. This type of lockout is usually due to low
gas line pressure. After one hour of continuous thermostat
demand for heat, the Watchguard will break and remake
thermostat demand to the furnace and automatically reset
the integrated control to begin the ignition sequence.
Issue 1933
NO JUMPER
achieve desired setting.
90 Second
120 Second
o Time
o Time
180 Second
o Time
507735-03
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