Lennox International Inc ML193DF Filters, Duct System, Pipe & Fittings Specifications

Models: MERIT SERIES GAS FURNACE DOWNFLOW AIR DISCHARGE ML193DF

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Filters

Filters

This unit is not equipped with a filter or rack. A field−pro- vided filter is required for the unit to operate properly. Table 3 lists recommended filter size.

A filter must be in place whenever the unit is operating.

 

TABLE 3

 

 

Furnace

Filter Size

Cabinet Width

 

 

 

 

17−1/2"

16 x 25 x 1 (1)

 

21"

 

Duct System

Use industry-approved standards to size and install the supply and return air duct system. Refer to ACCA Manual D. This will result in a quiet and low-static system that has uniform air distribution.

NOTE − This furnace is not certified for operation in heating mode (indoor blower operating at selected heating speed) with an external static pressure which exceeds 0.5 inches w.c. Operation at these conditions may result in improper limit operation.

Supply Air Plenum

If the furnace is installed without a cooling coil, a removable access panel should be installed in the supply air duct. The access panel should be large enough to permit inspection of the heat exchanger. The furnace access panel must al- ways be in place when the furnace is operating and it must not allow leaks into the supply air duct system.

Return Air Plenum

NOTE − Return air must not be drawn from a room where this furnace, or any other gas−fueled appliance (i.e., water heater), or carbon monoxide−producing de- vice (i.e., wood fireplace) is installed.

When return air is drawn from a room, a negative pres- sure is created in the room. If a gas appliance is operating in a room with negative pressure, the flue products can be pulled back down the vent pipe and into the room. This reverse flow of the flue gas may result in incomplete com- bustion and the formation of carbon monoxide gas. This raw gas or toxic fumes might then be distributed through- out the house by the furnace duct system.

Use fiberglass sealing strips, caulking, or equivalent seal- ing method between the plenum and the furnace cabinet to ensure a tight seal. If a filter is installed, size the return air duct to fit the filter frame.

Pipe & Fittings Specifications

All pipe, fittings, primer and solvent cement must conform with American National Standard Institute and the Ameri- can Society for Testing and Materials (ANSI/ASTM) stan- dards. The solvent shall be free flowing and contain no lumps, undissolved particles or any foreign matter that ad- versely affects the joint strength or chemical resistance of the cement. The cement shall show no gelation, stratifica- tion, or separation that cannot be removed by stirring. Re- fer to the table 4 below for approved piping and fitting ma- terials.

Duct System CAUTION

Solvent cements for plastic pipe are flammable liq- uids and should be kept away from all sources of ignition. Do not use excessive amounts of solvent cement when making joints. Good ventilation should be maintained to reduce fire hazard and to minimize breathing of solvent vapors. Avoid contact of cement with skin and eyes.

TABLE 4

PIPING AND FITTINGS SPECIFICATIONS

Schedule 40 PVC (Pipe)

D1785

 

 

Schedule 40 PVC (Cellular Core Pipe)

F891

 

 

Schedule 40 PVC (Fittings)

D2466

 

 

Schedule 40 CPVC (Pipe)

F441

 

 

Schedule 40 CPVC (Fittings)

F438

 

 

SDR−21 PVC or SDR−26 PVC (Pipe)

D2241

 

 

SDR−21 CPVC or SDR−26 CPVC (Pipe)

F442

 

 

Schedule 40 ABS Cellular Core DWV (Pipe)

F628

 

 

Schedule 40 ABS (Pipe)

D1527

 

 

Schedule 40 ABS (Fittings)

D2468

 

 

ABS−DWV (Drain Waste & Vent)

D2661

(Pipe & Fittings)

 

 

 

PVC−DWV (Drain Waste & Vent)

D2665

Pipe & Fittings)

 

 

 

PRIMER & SOLVENT CEMENT

ASTM

SPECIFICATION

 

 

 

 

 

PVC & CPVC Primer

F656

PVC Solvent Cement

D2564

 

 

CPVC Solvent Cement

F493

 

 

ABS Solvent Cement

D2235

 

 

PVC/CPVC/ABS All Purpose Cement For

D2564, D2235, F493

Fittings & Pipe of the same material

 

 

 

ABS to PVC or CPVC Transition Solvent

D3138

Cement

 

 

 

CANADA PIPE & FITTING & SOLVENT

MARKING

CEMENT

 

 

 

 

 

PVC & CPVC Pipe and Fittings

 

 

 

PVC & CPVC Solvent Cement

ULCS636

 

ABS to PVC or CPVC Transition Cement

 

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Lennox International Inc ML193DF installation instructions Filters, Duct System, Pipe & Fittings Specifications