Maytag POF1HD091AVFA, Installation, Operation And Maintenance Manual

Table C-4:  System and General Troubleshooting 

continued

Problem Possible 

Cause 

Remedy 

System temperature rise too 
high. 

System temperature rise ideally should not exceed 85°F. Check 
for clogged air filters. Check blower fan for excess dirt build-up 
or debris. Speed up blower fan if necessary. 

Poor “fan off” delay timing 
selection, (fan stops too soon). 

Check “fan off” delay timing setting. Use a duct thermometer in 
the supply air plenum take-off or first few inches of the supply air 
trunk duct. Ideally, the fan will shut off at a temperature of 90° - 
100°F. Manipulate the dip switch settings to come as close as 
possible to this “fan off” temperature. 

Fuel oil leak. 

Check fuel oil line for leaks. Repair or replace if necessary. 

Stack temperature too high. 

Check stack temperature. Stack temperatures will normally 
range from 350° to 450°F. Check draft regulator. Draft should be 
set to -0.02 in. w.c. 

Excessive fuel oil 
consumption. 

Thermostat improperly 
adjusted or in poor location. 

Check thermostat heat anticipator setting against measured 
amperage draw.  Increase heat anticipator setting if necessary. 
If the thermostat is being influenced by drafts, sunlight, duct 
work, etc., relocate to more suitable location. 

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 practical CO

2

 or lowest practical O

2

 content in 

the flue gases. See Burner Set Up. 

Too much smoke. 

Heat exchanger partially 
clogged. 

Check for soot build-up in heat exchanger flue passages, 
especially in the outer radiator. 

Poor alignment between oil 
burner blast tube and fire pot. 

Check alignment. Blast tube should be centered with fire pot 
burner opening. Oil burner head should be ¼ inch back from the 
inside surface of the fire pot. 

Flame impingement caused by 
Incorrect nozzle angle. 

Check nozzle size and angle. (See Appendix A). Check distance 
from head to inside surface of the fire pot. 

Soot building up on blast 
tube (end coning). 

Defective fire-pot 

Check fire-pot. Repair or replace. 

Airflow blocked or dirty air 
filter. 

Clean or replace air filter. 

Thermostat adjustments or 
location. 

Check thermostat heat anticipator setting against measured 
amperage draw.  Increase heat anticipator setting if necessary. 
If the thermostat is being influenced by drafts, sunlight, duct 
work, etc., relocate to more suitable location. 

Insufficient airflow. 

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 a duct 
thermometer to assess accuracy of limit control. Check for 
obstructions to airflow 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 
intermittently on overload. 

Check blower fan motor amperage draw. Check motor 
ventilation ports, clean if necessary. Replace motor if necessary. 

Furnace will not warm 
home to desired 
temperature. 

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. 

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