Operating instructions

24
Table C-2: System and General Troubleshooting continued
Problem Possible Cause Remedy
Too much smoke.
Insuffi cient combustion air
adjustment at oil burner, or
improper draft pressure.
Adjust oil burner combustion air band and draft regulator to gain highest
practical CO2 or lowest practical O2 content in fl ue gases.
See Burner Set Up.
Heat exchanger partially
clogged.
Check for soot build-up in heat exchanger fl ue passages, especially in
outer radiator.
Soot building up on blast
tube (end coning).
Poor alignment between oil
burner blast tube and fi re pot.
Check alignment. Blast tube should be centered with fi re pot burner
opening. Oil burner head should be ¼ inch back from inside surface of fi re
pot.
Flame impingement caused by
Incorrect nozzle angle.
Check nozzle size and angle. (See Appendix A).
Check distance from head to inside surface of fi re pot.
Defective fi re-pot Check fi re-pot. Repair or replace.
Furnace will not warm
home to desired
temperature.
Airfl ow blocked or dirty air fi lter. Clean or replace air fi lter.
Thermostat adjustments or
location.
Check thermostat heat anticipator setting against measured amperage
draw. Increase heat anticipator setting if necessary. If thermostat is being
infl uenced by drafts, sunlight, duct work, etc., relocate to suitable location.
Insuffi cient airfl ow.
Check all dampers. Open closed dampers including registers in unused
rooms.
Check system temperature rise. If temperature rise is too high, speed up
blower fan.
Defective high limit control.
Test high limit function of all limit switches. Use duct thermometer to verify
accuracy of limit control.
Check for obstructions to airfl ow around limit switch bimetal elements.
Replace control if necessary.
Under-sized nozzle.
Check nozzle. If problem is not caused by air fl ow problems, use larger
nozzle, if permitted by rating plate.
Blower fan motor stopping
intermittently on overload.
Check blower fan motor amperage draw.
Check motor ventilation ports, clean if necessary. Replace motor if
necessary.
Burner motor stopping
intermittently on overload.
Check burner motor. Replace if necessary.
Home does not heat
evenly
Improper distribution of heat. This is not likely to be a furnace problem. Balance duct system.
Supply air temperature
too hot.
Airfl ow blocked or dirty air fi lter. Clean or replace air fi lter.
Insuffi cient airfl ow.
Check all dampers. Open closed dampers including registers in unused
rooms.
Check system temperature rise. If temperature rise is too high, speed up
blower fan.
Supply air temperature
too cool.
Excess airfl ow. Check system temperature rise. Slow down blower fan if necessary.
Excessive duct losses.
Check supply air ductwork. Seal leaky joints and seams. Insulate ductwork
if necessary.
Supply air temperature
too cool during fi rst
moments of furnace cycle.
Fan control "fan on" setting too
low.
Increase "fan on” dipswitch settings on EFT if control has this option.
Register air defl ectors may help.
Excessive duct losses.
Check supply air ductwork. Seal leaky joints and seams. Insulate ductwork
if necessary.
APPENDIX C - SEQUENCE OF OPERATION AND TROUBLESHOOTING