# 47860A005
Page 18
Any conversion of a natural gas unit to pro-
pane gas must be done by qualified person-
nel using a conversion kit available from the
manufacturer, following the instructions in the
conversion kit. If done improperly, overfiring
of the burners and improper burner operation
can result. This can create carbon monoxide
which could cause asphyxiation.
WARNING
Pressure Switch Connection
Horizontal Installation – R to L Airflow
Figure 28
Pressure Switch Connection
Horizontal Installation – L to R Airflow
Figure 29
Outlet Duct
For installations not equipped with a cooling coil, a remov-
able access panel must be provided in the outlet duct. The
opening should be accessible when the furnace is placed
in service. Smoke or reflected light may be observed
inside the casing to indicate the presence of leaks in the
heat exchanger. The cover for the opening shall be
attached in such a manner as to prevent leaks. The
recommended opening size is 6" x 14" for all sizes.
Gas Supply and Piping
Refer to the furnace rating plate to make sure the furnace
is equipped to burn the gas supplied (natural or propane).
When an air conditioning unit is used in con-
junction with the furnace, the evaporator coil
must be installed in the discharge (supply) air.
Do not install an evaporator coil in the return
air; excessive condensation will occur within
the furnace.
CAUTION
Horizontal Installation
The unit is shipped from the manufacturer with a black
hose connected to the pressure switch. The other end of
the hose must be connected to the external drain trap.
Route hose through gas line access hole in cabinet. Then
connect to 1/4" barbed fitting on drain trap assembly.
For right to left airflow installations, see Figure 28. For left
to right airflow installations, see Figure 29.
Be sure that the pressure switch hose does not form
a trap to hold condensation that could form from the
flue gas. Hose may be cut shorter to avoid forming a
trap, if required.
Circulating Air Supply
When the furnace is installed so that the supply ducts
carry air circulated by the furnace to areas outside the
space containing the furnace, the return air shall be
handled by a duct or ducts sealed to the furnace casing
and terminated outside the space containing the furnace.
A return air duct system is recommended. If the unit is
installed in a confined space or closet, a return connection
must be run, full size, to a location outside the closet. The
air duct in the closet must be tight to prevent any entrance
of air from the closet into the circulating air.
If there is no complete return air duct system, the return
air connection must be sealed to the furnace casing and
run, full size, to a location outside the utility room or space
housing the furnace to prevent a negative pressure on the
venting system.
