Lennox International Inc O23V-70, O23V5-140 Servicing the Oil Burner, Servicing the Air Filter

causing the unit to start sooting/smoking, Things which might affect combustion include a nozzle going bad, draft that changes during different climatic condi- tions, dirty oil, dirt obstructing the air inlet, etc.

To build in a "window of operation," set up the burner to be 2% less in CO2, For example, if you find a reading of 12% CO2, adjust the air inlet shutter to increase the air and drop the CO2 to 10%,

5.Retest the Smoke--With a drop in the CO2 and in- crease in the air you should see that the smoke has re- turned to 0,

6.Retest the Overfire Draft--This test serves to con- firm that you have not increased the air too much, Again you do not want a positive pressure at the test port. It should still be 0.02 less than the draft pressure reading taken at the breach. You may need to increase the stack draft by adjusting the barometric draft con- trol,

7.Stack Temperature--Take a stack temperature read- ing in the vent pipe. Subtract the room air temperature from the stack temperature. This will give you the net stack temperature, Use the efficiency charts provided in most CO2 analyzers to determine furnace efficiency.

4, Remove the locking screw and cap from the observa- tion tube and with the spiral wire brush, reach upward toward the rear of the heat exchanger to clean out the crossover tube,

CAUTION

5, Replace the three clean out caps and flue access el- bow. Make sure locking screws are secure,

6, Brush out and vacuum the vent outlet area of the outer drum and replace vent pipe.

7, Clean around the burner, blower deck and vestibule area,

NOTE - A heat exchanger clean-out kit ABRSH380 (35K09) is available from Lennox.

Servicing the Oil Burner

The nozzle and oil filter must be checked before each heat- ing season. Also, recheck the conditions shown in the Oil Furnace Start-up Checklist (see page 24),

NOTE - Close the oil line shutoff valve if the burner is shut down for an extended period of time,

CAUTION

Servicing the Air Filter

NOTE - Under no circumstances should the access panels to the blower compartment be left off or left partially open, Throw-Away Type Filters--Check filters monthly and re- place when necessary to assure proper furnace operation, Replace filters with like kind and size filters,

Reusable Type Filters--Filters should be checked monthly and cleaned when necessary to assure proper fur- nace operation.

Servicing the Blower

Blower motor is prelubricated and sealed for extended op- eration. No further lubrication is required. Disconnect pow- er to unit before cleaning blower wheel for debris,

Inspecting the Flue Pipe

The flue pipe should be inspected annually by a qualified service technician, Remove and clean any soot or ash found in the flue pipe. Inspect pipe for holes or rusted areas, If replacement is necessary, replace with the same size and type as required by code. Inspect the flue draft control device and replace if found defective.

Cleaning the Heat Exchanger

1, Remove the vent pipe from the furnace,

2, Remove the locking screws and the caps from the clean out tubes, Remove flue access elbow.

3.Using a long spiral wire brush, sweep down the outer drum of the heat exchanger. Then using the hose at- tachment, vacuum out loose debris,

Page 18

1, Action: Thermostat calls for heat (W terminal is en- ergized)

Response:

•Blower control board closes oil primary control T-3T connections,

•After a 15-second pre-purge period, power is sent to the burner and ignition is established. When the burner pump reaches full speed, the solenoid valve is energized.

•Ignition system and oil primary control start the furnace. Oil flows as long as oil primary control senses flame.

•Burner motor energized and heat fan on ramp tim- ing begins. When timing is complete, the circulat- ing fan is at heat speed and warm air is delivered to the controlled space.

2, Action: Thermostat ends call for heat (W terminal is de-energized)

Response:

•Oil primary control is de-energized, terminating the burner cycle.

•Heat fan off ramp timing begins. When timing is complete, circulating fan is de-energized.

•Blower control board returns to standby mode (oil primary control and circulating fan are off).

•After the thermostat is satisfied, the thermostat circuit opens. The solenoid valve is de-energized before the pump rotation stops. Power to the burn- er is interrupted, shutting down the burner,

3, Action: Burner fails to light Response:

•Oil primary control locks out within lockout timing (timing depends on oil primary control),

•Burner motor is de-energized,

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