Rheem OBF Series Installation Instructions Manual page 24

COMPLAINT
Cad cell not functioning
Low CO
2
High stack temperatures
High smoke reading
Burner motor runs but does not fire
Poor draft - overfire and stack
Noisy Operation
24
CHECK FOR:
1. Requires direct view of flame
2. External light effecting cell operation
3. Remove cad cell and check with an ohmmeter:
a. With cad cell covered, the resistance should be over 100K ohms
b. With cad cell exposed to room light, the resistance should be
under 1.5 K ohms
1. High draft through furnace
2. Improper primary air adjustment
3. Damaged combustion chamber
4. Faulty nozzle
5. Incorrect oil pressure
6. Draft regulator improperly set
7. Incorrect fuel/air mixture
1. Damaged combustion chamber
2. Furnace not set-up with combustion kit
3. Undersized return air
4. Overfired furnace
5. Dirty heat exchanger
6. High draft, barometric damper not properly set
7. Excessive temperature rise
8. Air shutter adjustment open too much.
1. Lack of combustion air
2. Inadequate overfire draft
3. Incorrect oil pressure
4. Dirty burner blower wheel
5. Incorrect nozzle
6. Faulty oil pump
7. Dirty oil
8. Burner motor not obtaining full speed
9. Damaged combustion chamber
10. Flame impingement
11. Incorrect fuel/air mixture
1. Improperly sized chimney or not enough chimney height
2. Holes or cracks in chimney
3. Restricted chimney
4. Too many 90 degree elbows in vent pipe
5. Outside chimney too cool
6. Cool flue gases
7. Barometric damper not properly set, sticking or in wrong location
8. Oil furnace and fireplace chimney interconnected
9. Heat exchanger passages plugged
10. Overfired furnace
11. Improper air shutter adjustment
1. Bad coupling alignment
2. Air in oil supply line (use only good flare fittings)
3. Tank hum on two-pipe system and inside tank