Use of Furnace as Construction Heater

NOTE − Furnace must be adjusted to obtain a temperature rise within the range specified on the unit nameplate. Failure to do so may cause erratic limit operation and premature heat exchanger failure.

This ML193DF furnace must be installed so that its electri- cal components are protected from water.

Installation in Combination with a Cooling Coil

When this furnace is used with cooling units (figure 3), it shall be installed in parallel with, or on the upstream side of, cooling units to avoid condensation in the heating compart- ment. With a parallel flow arrangement, a damper (or other means to control the flow of air) must adequately prevent chilled air from entering the furnace. If the damper is manu- ally operated, it must be equipped to prevent operation of ei- ther the heating or the cooling unit, unless it is in the full HEAT or COOL setting.

When installed, this furnace must be electrically grounded according to local codes. In addition, in the United States, installation must conform with the current National Electric Code, ANSI/NFPA No. 70. The National Electric Code (ANSI/NFPA No. 70) is available from the following ad- dress:

National Fire Protection Association 1 Battery March Park

Quincy, MA 02269

In Canada, all electrical wiring and grounding for the unit must be installed according to the current regulations of the Canadian Electrical Code Part I (CSA Standard C22.1) and/or local codes.

Heating Unit Installed Parallell to Air Handler Unit

tent operation down to 55°F (13°C) dry bulb for cases where a night setback thermostat is used. Return air tem- perature must not exceed 85°F (29°C) dry bulb.

The ML193DF furnace may be installed in alcoves, closets, attics, basements, garages, utility rooms and crawl spaces.

This furnace design has not been CSA certified for installa- tion in mobile homes, recreational vehicles, or outdoors.

Never use an open flame to test for gas leaks. Check all connections using a commercially available soap solution made specifically for leak detection.

Lennox does not recommend the use of ML193DF units as a construction heater during any phase of construction. Very low return air temperatures, harmful vapors and op- eration of the unit with clogged or misplaced filters will dam- age the unit.

ML193DF units may be used for heating of buildings or structures under construction, if the following conditions are met:

• The vent system must be permanently installed per

these installation instructions.

• A room thermostat must control the furnace. The use of

fixed jumpers that will provide continuous heating is not

allowed.

• The return air duct must be provided and sealed to the

furnace.

• Return air temperature range between 60°F (16°C) and

80°F (27°C) must be maintained.

• Air filters must be installed in the system and must be

maintained during construction.

• Air filters must be replaced upon construction comple-

tion.

GAS UNIT

Dampers

(open during heating

operation only)

AIR HANDLER

Dampers

(open during cooling

operation only)

• The input rate and temperature rise must be set per the

furnace rating plate.

• One hundred percent (100%) outdoor air must be pro-

vided for combustion air requirements during construc-

tion. Temporary ducting may supply outdoor air to the

furnace. Do not connect duct directly to the furnace.

Size the temporary duct following these instructions in

section for Combustion, Dilution and Ventilation Air in a

confined space with air from outside.

• The furnace heat exchanger, components, duct system,

air filters and evaporator coils must be thoroughly

cleaned following final construction clean−up.

FIGURE 3

NOTE − This furnace is designed for a minimum continu- ous return air temperature of 60°F (16°C) or an intermit-

• All furnace operating conditions (including ignition, in-

put rate, temperature rise and venting) must be verified

according to these installation instructions.

Page 5