Page 75
Horizontal furnace (FIGURE  50)  -  In  horizontal 
furnace  applications  the  eld  provided  vent  must 
be  a  minimum  4”  to  a  maximum  5”  length  above 
the condensate drain outlet connection. Any length 
above 5” may result in a ooded heat exchanger if 
the  combined  primary  drain  line  were  to  become 
restricted.
NOTE - In horizontal applications it is recommended 
to install a secondary drain pan underneath the unit 
and trap assembly.
NOTE - Appropriately sized tubing and barbed tting 
may  be  used  for  condensate  drain.  Attach  to  the 
drain on the trap using a hose clamp. See FIGURE 
44.
Field Provided Drain Components
T
ubing
Hose Clamp
Barbed Fitting
Elbow
FIGURE 44 
 CAUTION
Do not use copper tubing or existing copper 
condensate lines for drain line.
6 -   If unit will be started immediately upon completion 
of installation, prime trap per procedure outlined in 
Unit Start-Up section.
Condensate line must slope downward away from the 
trap to drain.  If  drain  level is above  condensate  trap, 
condensate  pump  must  be  used.  Condensate  drain 
line should be routed within the conditioned space to 
avoid  freezing  of  condensate  and  blockage  of  drain 
line. If this is not possible, a heat cable kit may be used 
on the  condensate  trap  and  line. Heating  cable  kit  is 
available from Lennox in  various lengths; 6 ft. (1.8m) 
- kit no. 26K68; 24 ft. (7.3m) - kit no. 26K69; and 50 ft. 
(15.2m) - kit no. 26K70.
(Unit shownin upflow position withremote trap)
*5’ max.
To  Drain
PVCPipeOnly
FieldProvidedVent
Min.1” Above Condensate
Drain
Connection
1”
Min.
Trap CanBeInstalleda
Maximum 5’ From Furnac
e
2” Max.
CONDENSATE TRAP LOCATIONS
*Piping from furnace must slope down a
minimum 1/4” per ft. toward trap
FIGURE 45 
Coil Using A Separate Drain
Condensate
Drain
Connection
Field Provided Vent
(1” min. 2” max. above
condensate connection)
Evaporator drain
line required
(Trap at coil is optional)
FIGURE 46