Lennox Hearth CR-3835L, CST-38, CPF-38 Combustion AIR, Combustion Air Control, Lintel Extension

CAUTION: GLASS AND METAL FRAMES GET HOT — ALWAYS USE HANDLES TO OPEN AND CLOSE THE DOORS.

WARNING: CERTAIN MODEL FIRE- PLACES REQUIRE THAT THE GLASS DOORS BE CLOSED DURING OPERA- TION. BE AWARE THAT SAFETY GLASS IS UNPREDICTABLE WHEN HOT AND MAY BREAK, EXPELLING HOT GLASS INTO THE ROOM. ADVISE ALL FAMILY MEMBERS TO REMAIN WELL AWAY FROM THE FIREPLACE WHEN OPERAT- ING WITH DOORS CLOSED TO AVOID ANY POSSIBLE PERSONAL INJURY.

COMBUSTION AIR

A proper amount of combustion air is impor- tant for your fireplace. Fireplaces consume large amounts of oxygen. It is important to allow an adequate supply of air. If the fireplace is not equipped with an outside air kit, it may not obtain sufficient amounts of combustion air from inside the house or structure in which it is installed. Therefore, the fire may draw from an outside air source and pull air in through the chimney. This may cause smoke spillage into the room.

Smoke spillage often occurs when a fire is first started, until the fireplace and the chimney has had the opportunity to “come up to tempera- ture” and to begin to function normally. If smoke spillage problems persist, a window may be opened just a crack to allow the proper flow of combustion air to the fireplace.

If your fireplace is equipped with an outside combustion air kit, keep open at all times when fire is burning and close when fire is out to prevent cold air intrusion.

Combustion Air Control

The operation and location of the outside air control lever varies to some extent on different fireplace models.

On the CR Series fireplaces, the control lever that operates the outside combustion air valve has been pre-installed on your fireplace. A coverplate has been mounted over this control lever only if the outside air kit has not been attached. The control lever is located on the closed end of the fireplace opening behind the screen. To open the air damper, turn the lever handle 1/2 turn counter clockwise (or until lever can be moved upward), then re-tighten at desired open position. To close damper, re- verse procedure (Figure 5 ).

Control

Lever

Figure 5

On the Merit Series fireplaces, the control lever that operates the outside combustion air valve is located on one lower side behind the screen panel. Push the lever all the way in to open the air valve and pull the lever all the way out to close the air valve (Figure 6 ).

Open

Closed

Figure 6

The outside air damper should be kept closed on all fireplaces except when the fireplace is in operation. If there is no heat present in the firebox, the air damper should be closed at night before retiring to prevent intrusion of outside air into the home.

NOTE: DIAGRAMS & ILLUSTRATIONS NOT TO SCALE

LINTEL EXTENSION

These Merit Multi-Open Factory-Built Fireplaces were designed, tested and listed with an 18" (457 mm) high viewing area, floor to lintel. However, varying conditions such as altitude, climate, wood type, moisture content of fuel, dwelling design peculiarities, average ambient air pressure and humidity may effect the performance of this fireplace. If an unac- ceptable amount of smoking occurs while the doors are open, the adjustable lintel can be moved to correct the smoking condition.

The lintel extension can be lowered a maxi- mum of 2" (51 mm) using a predrilled hole located at the top of the lintel extension. To lower the lintel extension 1" (25 mm), drill a 1/8" (3 mm) hole where the dimple is located. (See Figure 7.)

To lower the lintel extension on Model CST-38, remove the two screws from both ends of the lintel extension (located behind the screen assembly). Slide the lintel extension down and align the desired holes in the lintel extension with the holes in the lintel frame. Reattach using the screws previously removed. Repeat this procedure for the lintel extension on the opposite side of the fireplace. (Figure 7 )

Front

Frame

Lintel

Frame

Original Position

Lowest

DimplePosition

2" (51 mm)

Lintel

Extension

Figure 7

On Model CPF-38 the two (2) side lintel exten- sions are welded to the end lintel extension. The lintel extension lowers similarly to the CST-38 lintel extension. However, to prevent the end lintel extension from being misshaped, follow the following steps while referring to Figure 7.

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