Lennox International Inc ML193UH installation instructions Field Provided Drain Components

NOTE - If necessary the condensate trap may be installed up to 5’ away from the furnace. Use PVC pipe to connect trap to furnace condensate outlet. Piping from furnace must slope down a minimum of 1/4” per ft. toward trap.

1 - Determine which side condensate piping will exit the unit, location of trap, field-provided fittings and length of PVC pipe required to reach available drain.

2 - Use a large flat head screw driver or a 1/2” drive socket extension and remove plug (figure 46) from the cold end header box at the appropriate location on the side of the unit. Install provided 3/4 NPT street elbow fitting into cold end header box. Use Teflon tape or appropri­ ate pipe dope.

3 - Install the cap over the clean out opening at the base of the trap. Secure with clamp. See figure 54.

4 - Install drain trap using appropriate PVC fittings, glue all joints. Glue the provided drain trap as shown in fig­ ure 54. Route the condensate line to an open drain. Condensate line must maintain a 1/4” downward slope from the furnace to the drain.

CONDENSATE TRAP AND PLUG LOCATIONS

(Unit shown in upflow position)

Trap

(same on

right side)

1-1/2 in.

Plug

(same on left side)

NOTE - In upflow applications where side return air filter is installed on same side as the conden­ sate trap, filter rack must be installed beyond condensate trap or trap must be re-located to avoid interference.

FIGURE 46

5 - Figures 49 and 51 show the furnace and evaporator coil using a separate drain. If necessary the conden­ sate line from the furnace and evaporator coil can drain together. See figures 50, 52 and 53.

Upflow furnace (figure 52) - In upflow furnace applica­

tions the field provided vent must be a minimum 1” to a maximum 2” length above the condensate drain outlet connection. Any length above 2” may result in a flooded heat exchanger if the combined primary drain line were to become restricted.

Horizontal furnace (figure 53) - In horizontal furnace applications the field provided vent must be a mini­ mum 4” to a maximum 5” length above the condensate drain outlet connection. Any length above 5” may re­ sult in a flooded heat exchanger if the combined pri­ mary 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 fitting may be used for condensate drain. Attach to the drain on the trap using a hose clamp. See figure 47.

6 - If unit will be started immediately upon completion of installation, prime trap per procedure outlined in Unit Start-Up section.

Field Provided Drain Components

Elbow

Barbed Fitting

Tubin
g	Hose Clamp

FIGURE 47

CAUTION

Do not use copper tubing or existing copper conden­ sate lines for drain line.

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.

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