Unitary Products Group
15
035-14289-000 Rev. A (0701)
PROBLEM
POSSIBLE CAUSE
REMEDY
Oil burner sputtering at
nozzle
Electrodes out of adjustment
or defective
Check electrode settings. Check electrodes for dirt build-up or
cracks in porcelain.
Poor transformer high voltage
connections or defective
transformer
Check contacts between transformer and electrodes. If OK, replace
transformer.
Fuel oil filter clogged
Replace fuel oil storage tank filter and/or fuel oil in-line filter
Defective oil pump
Check burner motor/fuel oil pump coupling. Check oil pump pres-
sure. Replace fuel oil pump if necessary.
Fuel oil line partially clogged
or contains air
Bleed air from oil line. If problem persists, replace oil line.
Excessive fuel oil con-
sumption
System temperature rise too
high
System temperature rise should not exceed 85
°
F. Check for
clogged air filters. Check blower fan for excess dirt build-up or de-
bris. Speed up blower fan if necessary.
Blower fan control out of ad-
justment, (fan stops too soon)
Check fan control settings. The fan control is adjusted with a duct
thermometer in the supply air plenum take-off or first few inches of
the supply air trunk duct. The “fan off” setting should be 90
°
- 100
°
F.
Once set, the “fan on” setting is normally adjusted 25
°
-30
°
F higher
than the “fan off” setting.
Fuel oil leak
Check fuel oil line for leaks. Repair or replace if necessary.
Stack temperature too high.
Thermostat improperly ad-
justed or in poor location.
Check stack temperature. Stack temperature will normally range
from 350
°
to 450
°
F. Check draft regulator. Draft should be set to
0.02" WC.
Check thermostat heat anticipator setting against measured amper-
age draw. Increase heat anticipator setting if necessary. If the ther-
mostat is being influenced by drafts, sunlight, duct work, etc,
relocate to a more suitable location.
Too much smoke
Insufficient combustion air
adjustment at oil burner, or
improper draft pressure
Adjust the oil burner combustion air band and draft regulator to gain
the highest CO
2
possible with a Bacharach No.1 smoke.
Heat exchanger partially
clogged
Check for soot build-up in heat exchanger flue passages, especially
in the outer radiator.
Furnace will not warm
home to desired tempera-
ture
Air flow blocked by dirty air
filter
Clean or replace air filter
Thermostat adjustments or
location
Check thermostat heat anticipator setting against measured amper-
age draw. Increase heat anticipator setting if necessary. If the ther-
mostat is being influenced by drafts, sunlight, duck work, etc,
relocate to more suitable location.
Insufficient air flow
Check all dampers. Open closed dampers including registers in un-
used 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 a duct thermometer
to assess accuracy of limit control. Check for obstructions to air flow
around limit switch bi-metal elements. Replace control if necessary.
Under-sized nozzle.
Check nozzle. If problem is not caused by air flow problems, use
larger nozzle, if permitted by rating plate.
Blower fan motor stopping in-
termittently on overload
Check blower fan motor amperage draw. Check motor ventilation
ports, clean if necessary. Replace motor if necessary.
Burner motor stopping inter-
mittently on overload
Check burner motor. Replace if necessary.
Home does not heat
evenly
Improper distribution of heat
This is not likely to be furnace problem. Balance duct system.
Supply air temperature too
hot
Air flow blocked or dirty air fil-
ter
Clean or replace air filter.
Insufficient air flow
Check all dampers. Open closed dampers including registers in un-
used rooms. Check system temperature rise. If temperature rise is
too high, speed up blower fan.
Supply air temperature too
cool
Fan control “fan on” setting
too low
Check system temperature rise. Slow down blower fan if necessary.
Excessive duct losses
Check supply air duct work. Seal leaky joints and seams. Insulate
ductwork if necessary.
SYSTEM TROUBLESHOOTING - CONT'D
