American Standard CUX1B040A9241A Installation, Operation And Maintenance Manual page 24

Installation Instructions
DOWNFLOW (HORIZONTAL)
Connections must be made to an OPEN/VENTED DRAIN.
Outdoor draining of the furnace and coil condensate is permis-
sible if allowed by local codes. Caution should be taken to prevent
drains from freezing or causing slippery conditions that could lead
to personal injury. Excessive draining of condensate may cause
saturated ground conditions that may result in damage to plants.
NOTE:
Use 1/2" or larger PVC or CPVC pipe and fittings as required
for drain connections (fittings, pipe and solvent cement not
provided).
NOTE:
A corrosion resistant condensate pump must be used if a
pump is required for a specific drain system.
IMPORTANT:
The condensate drain should be installed with provisions to
prevent winter freeze-up of the condensate drain line. Frozen
condensate will block drains, resulting in furnace shutdown. If the
drain line cannot be installed in a conditioned space, then UL
listed heat tape should be applied as required to prevent freezing
(per manufacturer's instructions). The heat tape should be rated at
5 or 6 watts per foot at 120 volts. Self-regulating (preferred) or
thermostatically controlled heat tape is required.
Evaporator and furnace condensate drain
manifolded together. A primary drain vent stack must be in-
stalled and terminated below the outlet of the secondary heat
exchanger drain connection to prevent water from damaging
furnace controls if the primary drain outlet plugs up. Where the
furnace is installed above a finished ceiling, the primary drain
vent stack must be installed such that overflow from the vent
stack opening will flow into an axillary drain pan in order to
prevent water damage to the finished ceiling below.
Page 24
Cut off curved end of
Inducer drain hose
piping may be
If upflow furnace is installed
over a finished ceiling, overflow
from the primary drain vent
stack must flow into an auxillary
drain pan to prevent damage to
the finished ceiling below.
Primary drain vent stack
must terminate below
secondary heat exchanger
condensate drain outlet.
To drain opening
Pub. No. 41-5016-12