Question 1

When the CAD cell is in darkness, it will have a very high resistance of several ____ ohms.&#10;A) hundred&#10;B) thousand&#10;C) hundred thousand&#10;D) million

Accepted Answer

In darkness, a CAD cell (cadmium sulfide cell) has a very high resistance, typically in the range of several hundred thousand ohms.

Question 2

The primary control controls the major operation of an oil-fired heating system.

Accepted Answer

The primary control is responsible for controlling the major operation of an oil-fired heating system, including starting and stopping the burner, and monitoring the oil supply and flame.

Question 3

The CAD cell changes its resistance in accordance with the amount of light to which it is exposed.

Accepted Answer

The CAD cell, also known as a photoresistor, is a light-dependent resistor that changes its resistance based on the intensity of light it is exposed to.

Question 4

The air produced by the combustion fan motor causes the arc to be blown in a ____ shape.&#10;A) horseshoe&#10;B) star&#10;C) ring&#10;D) donut

Accepted Answer

The combustion fan motor blows air in a horseshoe shape, which causes the arc to be blown in the same shape. This helps with the stability and efficiency of the arc.

Question 5

Primary controls employ the ____ with other solid-state components in its operation.&#10;A) diode&#10;B) lead sulfide cell&#10;C) thermistor&#10;D) triac

Accepted Answer

The triac is a solid-state component that is commonly used in primary controls in order to regulate the flow of electricity.

Question 6

A gun-type oil furnace is ignited by an electric arc.

Accepted Answer

A gun-type oil furnace is ignited by an electric spark, not an electric arc.

Question 7

Some of the controls on an oil-fired heating system are basically the same as the controls on a gas-fired system.

Accepted Answer

Many of the controls, such as the thermostat, pressure gauge, and limit switch, are similar on both oil-fired and gas-fired heating systems. However, there are some differences in the controls specific to each type of system.

Question 8

Oil-fired systems are generally ignited by a high-voltage transformer producing an arc across two electrodes located near the ____.&#10;A) transformer&#10;B) nozzle&#10;C) triac&#10;D) cell

Accepted Answer

The electrodes are located near the nozzle, which is where the oil is atomized and sprayed into the combustion chamber for ignition.

Question 9

When the CAD cell is in darkness, its resistance will decrease to about 50 ohms.

Accepted Answer

When the CAD cell is in darkness, its resistance will increase (not decrease) to about 1 megaohm.

Question 10

The primary control must ensure that ignition is established in the combustion chamber to prevent an accumulation of ____ vapor.&#10;A) cadmium sulfide&#10;B) silicon&#10;C) oil&#10;D) water

Accepted Answer

The primary control in a combustion chamber must establish ignition to prevent an accumulation of oil vapor which can be dangerous and lead to a fire or explosion. Sources of oil vapor can include fuel leaks or incomplete combustion from poor maintenance or improper adjustments. Therefore, it is crucial that the primary control is functioning properly to prevent any potential hazards.

Deck 39: Oil Burner Controls