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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 20 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.
Blower Control
The blower ON time of 30 seconds is not adjustable. The
blower OFF delay (amount of time that the blower operates
after the heat demand has been satisfied) is 120 seconds
and is not adjustable.
Natural to LP/Propane
Model
0 - 7500 ft
(0 - 2286m)
045
070
11K48
090
110
*Conversion requires installation of a gas valve manifold spring which is provided with the gas conversion kit.
Pressure switch is factory set. No adjustment necessary. All models use the factory-installed pressure switch from 0-4500 feet (0-
1371 m).
Table 19. Conversion Kit Fan Pressure Switch Requirements at Varying Altitudes
508391-01
High Altitude Natural
Burner Orifice Kit
7501 - 10000 ft
(2286 - 3048m)
*51W01
Issue 2327
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.
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____________
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.
Exhaust and Air Intake Pipe
1.
Check exhaust and air intake connections for tightness
and to make sure there is no blockage.
2.
Is pressure switch closed? Obstructed exhaust pipe
will cause unit to shut off at pressure switch. Check
termination for blockages.
3.
Obstructed pipe or termination may cause rollout
switches to open. Reset manual flame rollout switches
on burner box assembly if necessary.
High Altitude LP/Propane
Burner Orifice Kit
7501 - 10000 ft
(2286 - 3048m)
11K47
High Altitude Pressure Switch
4501 - 7500 ft
7501 - 10000 ft
(1371 - 2286m)
(2286 - 3048m)
14A51
14A53
14A48
14A54
14A54
14A53
25B93
14A45
Page 47 of 52
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