Page 24
TABLE 11
Manifold Pressure Settings at all Altitudes
Model
Input Size
Gas 0 - 4500 ft. 4501 - 7500 ft . 7501 - 10,000 ft.
Line Pressure in. wg.
Min Max
045
Nat 3.5 3.5 3.5 4.5 13.0
LP/Propane 10.0 10.0 10.0 11.0 13.0
070
Nat 3.5 3.3 3.5 4.5 13.0
LP/Propane 10.0 10.0 10.0 11.0 13.0
090
Nat 3.5 3.3 3.5 4.5 13.0
LP/Propane 10.0 10.0 10.0 11.0 13.0
110
Nat 3.5 3.3 3.5 4.5 13.0
LP/Propane 10.0 10.0 10.0 11.0 13.0
TABLE 12
Pressure Switch and Gas Conversion Kits at all Altitudes
Model Input
Size
High Altitude Pressure Switch Kit Natuarl Gas Orice Kit LP/Propane Orice Kit
045 0-4500 ft 4501-7500 ft 7501-10,000 ft 0 - 7500 ft 7501 - 10,000 ft 0 - 7500 ft 7501 - 10,000 ft
070
No Change
No Change
80W51 73W81 73W37 11K49 11K44
110 80W52
090 No Change
090 (X)
80W52
110
NOTE - A natural to L.P. propane gas changeover kit is necessary to convert this unit. Refer to the changeover kit instal-
lation instruction for the conversion procedure.
Other Unit Adjustments
NOTE - Do not secure the electrical conduit directly to the
air ducts or structure.
Primary and Secondary Limits
The primary limit is located on the heating compartment
vestibule panel. The secondary limits (if equipped) are lo-
cated in the blower compartment, attached to the back
side of the blower. These auto reset limits are factory-set
and require no adjustment.
Flame Rollout Switch
The manually reset switch is located on the front of the
burner box.
Pressure Switch
The pressure switch is located in the heating compartment
adjacent to the combustion air inducer. The switch checks
for proper combustion air inducer operation before allow-
ing ignition trial. The switch is factory-set and requires no
adjustment.
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. Increase the blower speed to de-
crease the temperature. Decrease the blower speed to
increase the temperature rise. Failure to adjust the tem-
perature rise may cause erratic limit operation.
Fan Control
The heat fan-on time of 30 seconds is not adjustable. The
heat fan-off delay (amount of time that the blower oper-
ates after the heat demand has been satised) may be
adjusted by changing the jumper position across the ve
pins on the integrated control. The unit is shipped with a
factory fan-off delay setting of 120 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 gure 23.
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