5
PRODUCT DESIGN
Alcove Illustration
REAR
S
ID
E
S
ID
E
ALCOVE
24" at front is required for servicing or cleaning.
Note:
In all cases accessibility clearance shall take
precedence over clearances from the enclosure where
accessibility clearances are greater. All dimensions are
given in inches.
High Altitude Derate
When this furnace is installed at high altitude, the appropri-
ate High Altitude orifice kit must be installed. This is re-
quired due to the natural reduction in the density of both the
gas fuel and combustion air as altitude increases. The kit
will provide the proper design certified input rate within the
specified altitude range.
High altitude kits are purchased according to the installa-
tion altitude and usage of either natural or propane gas. Refer
to the chart above for a tabular listing of appropriate altitude
ranges and corresponding manufacturer’s high altitude Natu-
ral Gas and Propane Gas kits. For a tabular listing of appro-
priate altitude ranges and corresponding manufacturer's High
Altitude Pressure Switch kits, refer to either the
Pressure
Switch Trip Points & Usage Chart
in this manual or the
Ac-
cessory Charts
in Service Instructions.
2000
3000
4000
4500
5000
6000
7000
8000
US BURNER
ORIFICE
44/55
44/55
45/56
45/56
46/57
47/58
47/58
CANADA BURNER
ORIFICE
44/55
47/57
HA-02 HIGH ALTITUDE CONVERSION KIT REQUIRED
Tabled data is based upon the furnace input being reduced for altitudes above sea level. U.S. 4% per 1,000 feet.
Canada 10% derate for 2,000-4,000 feet.
ELEVATION ABOVE SEA-LEVEL (FEET)
INPUT PER BURNER - 22,500 BTUH NATURAL GAS / 20,000 BTUH L.P.
Single Stage Thermostat
A single-stage thermostat with only one heating stage may
be used to control this furnace. The application of a single-
stage thermostat does not offer “true” thermostat-driven two-
stage operation, but provides a
timed
transition from low to
high fire. The furnace will run on low stage for a fixed period
of time before stepping up to high stage to satisfy the
thermostat’s call for heat. The delay period prior to stepping
up can be set at either a fixed 5 minute time delay or a load
based variable time between 1 and 12 minutes (AUTO mode).
If the AUTOmode is selected, the control averages the cycle
times of the previous three cycles and uses the average to
determine the time to transition from low stage to high stage.
To use a single-stage thermostat, turn off power to the fur-
nace, move the thermostat selection DIP switch to the OFF
position. Set the desired transition time by setting the tran-
sition delay DIP switch to the desired ON/OFF position. Turn
power back on. Refer to the following figure.
3
4
Thermostat
Stage Delay
Move to the ON position
to select two-stage
thermostat or OFF to
select single stage
thermostat
Move to the ON position
to select Auto transition
delay or OFF for 5 minute
transition delay
Heat OFF Delay
DIP Switches
ON
OFF
S1
