This document is a user manual for a Sears Gas-Fired Forced Air Wall Furnace, specifically models 867.736349 and 867.736389. It provides comprehensive information on installation, operation, maintenance, and repair parts.
Function Description
The Sears Gas-Fired Forced Air Wall Furnace is designed to provide forced air heating for residential spaces. It operates by burning natural gas or LP gas to heat air, which is then circulated throughout the room. The "forced air" aspect implies the use of a fan to distribute the heated air, ensuring efficient and even warmth. The "wall furnace" designation indicates that the unit is designed for installation within a wall, offering a space-saving heating solution.
Important Technical Specifications
The manual details several technical specifications crucial for proper installation and operation:
- Fuel Type: The furnace is designed to operate on either Natural Gas (Nat.) or Liquefied Petroleum (L.P.) gas. It is critical to ensure the correct fuel type is used for the specific model.
- BTU/HR Input:
- Model 867.736349 (Nat. Gas): 65,000 BTU/HR
- Model 867.736349 (L.P. Gas): 65,000 BTU/HR
- Model 867.736389 (Nat. Gas): 45,000 BTU/HR
- Model 867.736389 (L.P. Gas): 45,000 BTU/HR
- Main Burner Orifice Drill Size:
- Model 867.736349 (Nat. Gas): .1065"
- Model 867.736349 (L.P. Gas): .0635"
- Model 867.736389 (Nat. Gas): .1065"
- Model 867.736389 (L.P. Gas): .0635"
- Pilot Orifice Decimal:
- Model 867.736349: .018"
- Model 867.736389: .018"
- Electrical Supply: The furnace requires a 115V, 60Hz, 15 Ampere circuit from a separate circuit breaker or fuse. The wiring diagram illustrates the electrical connections, including the fan motor, limit control, transformer, and thermostat.
- Ventilation: Proper ventilation is essential. The manual specifies minimum clearances for combustion air and vent pipe installation. For natural gas, a minimum of 5 inches water column and for LP gas, 11 inches water column are required for gas supply pressure to the furnace control valve.
- Vent Pipe Requirements: The manual outlines specific requirements for vent pipe size and installation, including the use of a 4" round, double wall Type B-1 vent pipe. It also details the installation of vent shields and rear wall registers as optional accessories for specific venting configurations.
- Mounting: The furnace is designed for wall installation, either recessed or surface mounted. Specific instructions are provided for locating studs, cutting wall openings, and securing the unit.
- Gas Connection: A 1/2 inch steel or wrought iron pipe and fittings are required for the gas supply connection. A 1/8 NPT (National Pipe Thread) plugged hole is provided for test gauge connection.
Usage Features
The manual provides detailed instructions for operating the furnace, ensuring safe and efficient use:
- Lighting the Furnace: A step-by-step procedure is outlined for lighting the pilot and main burners. This includes setting the selector switch to "ON," turning the gas cock knob to "PILOT," depressing and holding the knob while lighting the pilot, and then turning the knob to "ON" after the pilot is established.
- Thermostat Control: The furnace is controlled by a thermostat, allowing users to set the desired room temperature. The manual explains how to adjust the thermostat for optimal comfort.
- Air Shutter Adjustment: Instructions are provided for adjusting the air shutter to achieve the proper flame mixture for the burners. This involves observing the flame color (inner cones light blue, outer mantle light blue) and adjusting the screw accordingly.
- Gas Cock Knob Settings: The gas cock knob has "ON," "OFF," and "PILOT" settings, which are used during the lighting and shutdown procedures.
- Limit Control: The furnace is equipped with a limit control to prevent overheating. If the furnace overheats, the limit control will shut off the main burners.
- Manual Selector Switch: The fan motor can be controlled by a manual selector switch, offering "SUMMER" (fan only) and "AUTO" (fan operates with heating) settings. There are also high and low fan speed settings.
- Safety Precautions: The manual emphasizes critical safety rules, including never storing or using gasoline or other flammable vapors near the furnace, not touching hot surfaces, never using an open flame to check for gas leaks, and immediately calling a gas supplier if gas is smelled. It also warns against installing the furnace in a mobile home, trailer, or recreational vehicle.
Maintenance Features
Regular maintenance is crucial for the longevity and safe operation of the furnace. The manual outlines several key maintenance tasks:
- Annual Upkeep: It is recommended to remove the cabinet door and front panel annually to clean the fan blades, fan motor, air shutters, and exposed air passages. A brush is suggested for cleaning.
- Oiling: Five drops of SAE 20 non-detergent oil should be applied to each of the two oil cups on the fan motor.
- Venting System Check: Regularly check that no parts of the venting system are blocked or rusted. Clean or replace parts as necessary.
- Burner and Pilot Flame Check: Periodically inspect the burner and pilot flames for proper appearance. Abnormal flame appearance may indicate a need for service.
- Cabinet Finish: The cabinet finish can be maintained by applying a small amount of furniture wax to a soft cloth and wiping clean. Abrasives or harsh cleaners should not be used.
- Furnace Area: Keep the area near the furnace clear from combustible materials, gasoline, and other flammable liquids and vapors.
- Combustion and Ventilation Air Supply: Ensure that the combustion and ventilation air supply is not blocked.
- Professional Service: For any abnormal appearance or if you suspect a problem, it is recommended to call a Sears service technician. The manual also provides a "Service Hints" section to help diagnose common issues.
- Cleaning: The manual advises cleaning the fan blades, fan motor, air shutters, and exposed air passages annually.
- Gas Leaks: If a gas leak is suspected, immediately call the gas supplier. Never use an open flame to check for leaks.
- Electrical Wiring: Ensure all electrical work conforms to local codes and ordinances, and is performed by a qualified electrician.
- Checks and Adjustments: The manual includes sections on adjusting the pilot burner, air for burners, and main burner, which are typically performed during professional service or troubleshooting.
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