27
OTHER UNIT ADJUSTMENTS
PRIMARY AND SECONDARY LIMITS
The primary limit is located on the heating compartment
vestibule panel. The secondary limits (if equipped) are
located in the blower compartment, attached to the back
side of the blower. These auto reset limits are factory-set
and require no adjustment.
FLAME ROLL-OUT SWITCHES
This manually reset switches are located on the top 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 allowing
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 stabilise, 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 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 heat
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 fan-
off delay setting of 60 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 32°C and 43°C at the moment that the blower is
de-energised. Longer off delay settings provide lower return
air temperatures; shorter settings provide higher return air
temperatures. See Figure 20.
HEAT-FAN OFF TIME IN SECONDS
Figure 20
NOTE:
Do not secure the electrical conduit directly to the air
ducts or structure.
HEAT FAN OFF TIME IN SECONDS
To adjust fan-off timing, reposition jumper across pins to
achieve desired setting.
NO JUMPER
60 90
120 180
60 90
120 180
60 90
120 180
60 90
120 180
60 Second
off Time
90 Second
off Time
120 Second
off Time
180 Second
off Time
Table 5
Pressure Switch and Gas Conversion kits at all Altitudes
Model
Input
Size
High Altitude
Pressure Switch kit
High Altitude
Natural Gas
Burner Orifice
kit
Natural Gas to LP/
Propane Gas Change
over kit
LP/Propane to
Natural Gas
Change over kit
0-610m
(0-2000 ft)
611-1219m
(2001-4000 ft)
1220-1981m
(4001-6500 ft)
1525-1981 m
(5001-6500 ft)
0-1524m
(0-5000
ft)
1525-
1981m
(5001-
6500 ft)
1-1524m
(1 5000 ft)
070
No Change
80W51
80W56
73W37
96W94
97W04
96W95
090
80W51
80W56
110
80W51
80W56
135
80W52
80W51
NOTE:
A natural to L.P. propane gas changeover kit is necessary to convert this unit. Refer to the changeover kit installation
instruction for the conversion procedure.
