NATE Oil Heating 2

Question 1

What does a #2 fuel oil supply line's two-pipe system accomplish compared to a single-pipe system?

Accepted Answer

Returns unused oil to the tank, preventing vapor lock and allowing the tank to be below the burner

Answer

A two-pipe system continuously circulates oil back to the tank, preventing air and vapor buildup and allowing a below-burner tank installation.

Question 2

What is the purpose of the electrodes in an oil burner?

Accepted Answer

Produce a high-voltage spark to ignite the atomized oil-air mixture

Answer

Electrodes are positioned in the air-oil spray and produce a continuous or intermittent spark to ignite the mixture at startup.

Question 3

What condition does a high CO2 reading combined with a high smoke number indicate on a combustion analysis?

Accepted Answer

Too little combustion air (rich mixture causing incomplete combustion)

Answer

High CO2 with high smoke indicates insufficient air, producing a rich mixture with incomplete combustion and carbon soot.

Question 4

What is the function of the delayed oil valve (solenoid valve) on some oil burners?

Accepted Answer

Stop oil flow immediately on burner shutdown to prevent after-drip and after-fire

Answer

The delayed oil valve closes instantly when the burner shuts off, preventing oil drip into the combustion chamber that could cause after-fire and smoke.

Question 5

What is a puffback in an oil heating system?

Accepted Answer

Small backfire explosion caused by igniting accumulated unburned oil in the combustion chamber

Answer

A puffback occurs when oil mist accumulates before ignition and ignites suddenly, causing a small explosion that can spread soot throughout the home.

NATE - North American Technician Excellence Practice Test

NATE - North American Technician Excellence Practice Test

NATE Oil Heating 2