18-CD25D1-2
25
Installer’s Guide
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 condi-
tioned space and/ or its surrounding ambient tempera-
ture is expected to fall below freezing, then 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 re-
quired.
Typical sources of UL listed heat tapes are W.W.
Granger, Inc. (Wintergard Plus
TM
Series), McMaster
Carr Supply Co. (3554 Series), or your equipment sup-
plier.
The condensate drain may be cleaned or inspected by
removal of the drain tube at the header.
Evaporator and Furnace condensate drain piping may
be manifolded together as shown in Figure 29. A pri-
mary drain vent stack must be installed 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 in-
stalled such that overflow from the vent stack
opening will flow into an auxiliary drain pan in
order to prevent water damage to the finished
ceiling below.
ALL HORIZONTAL APPLICATIONS
ARE LEFT SIDE DRAIN ONLY
TO
OPEN/
VENTED
DRAIN
UPFLOW FURNACE ON LEFT SIDE
WITH LEFT DRAIN SHOWN
HEADER
Figure 28
Primary drain vent stack
must terminate below
secondary heat exchanger
condensate drain outlet.
To drain opening
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.
Figure 29
