Possible cures: Get some fuel. Check for a blown fuse or open circuit breaker, or if a switch has been left off, said Markarian.
Check for broken wire(s); trace path of electricity, stated Sweigart. Turn the thermostat well above room temperature. Check to see if filter/ductwork is blocked or restricted, or the blower/motor is not operating, Sweigart added.
Possible cures: Get fuel; check for plugged nozzle, filter, or oil line, Markarian said. Open valve. Replace cracked porcelains.
Test and replace transformer/ igniter if necessary, said Sweigart. Adjust electrodes. Adjust air, then perform a combustion analysis. Test oil pump. Replace stripped pump coupling.
Possible cures: Clean or replace the nozzle, adjust the burner according to manufacturer’s specifications, or replace the end cone, noted Markarian.
Adjust air and perform a combustion analysis, Sweigart stated. Check chimney condition and heat exchanger condition. Check manufacturer’s ratings plate for the correct nozzle size, spray pattern, angle, and oil pump pressure, he added.
Possible cures: Set firing rate within specifications, Markarian said. Check thermostat.
Adjust the heat anticipator to manufacturer’s recommendation or measure the current and set accordingly, commented Sweigart. Set limit settings to achieve the manufacturer’s recommended temperature rise and comfort level of the occupant. Survey the duct system and make any necessary changes. Set blower speed to achieve the manufacturer’s recommended temperature rise. Close doors and windows.
Sweigart notes that the furnace may need cleaning; it may have the wrong nozzle; oil pump pressure is elevated; the ductwork leaks; ductwork is uninsulated; the home doesn’t have the right amount of insulation or has leaky windows and doors; or the doors and windows are being left open.
Possible cures: If replacing, perform a load calculation to determine the correct size and install a properly sized unit. Make adjustments using instruments, said Markarian.
Have the furnace cleaned annually, stated Sweigart. Install the correct nozzle. Check and adjust oil pump pressure. Seal duct leaks. Insulate ductwork. Recommend that the homeowner invest in energy conservation items. Instruct occupants to keep doors and windows closed.
Other causes, said Sweigart, are delayed ignition, the heat exchanger and/or chimney needs cleaning, combustion air has been hindered, or items are being stored too close to the smoke pipe or furnace.
Possible cures: Clean or replace the nozzle, adjust the burner, or replace the end cone, Markarian said. Check for a cracked heat exchanger and replace.
Correct the delayed ignition, said Sweigart. Clean the furnace/chimney. Do a combustion analysis to determine what is hindering the combustion air. Move items from the furnace room and instruct the occupant to keep the necessary clearance from this heat-generating appliance.
In addition, noted Sweigart, this situation could be caused by poor draft, a chimney in poor condition, or elevated oil pump pressure.
Possible cures: Adjust the burner or have the chimney cleaned, Markarian remarked.
Check draft and adjust properly or install a draft inducer if necessary, Sweigart said. Install an approved chimney liner. Verify nozzle size and double-check oil pump pressure and nozzle combination.
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Publication date: 12/16/2002