ACR 105 Final

The automatic control of a system is intended to ___.

• evaluate overloading situations

• maintain safe operations for service technicians

• maintain stable or constant conditions without excessive human interference

• maintain the working conditions of the equipment with a controllable device

Modulating controls are used to ___.

• start motors

• stop the flow of a liquid

• vary the speed of a motor

• stop motors

A thermal system overload may occur if a specific electrical or mechanical component is not cooled properly, resulting in ___.

• overheating

• underheating

• stable temperature

• constant temperature

The metals most often used in a bimetal temperature control are ____.

• copper and brass

• brass and steel

• copper and steel

• brass and aluminum

The Bourdon tube ____.

• curls inward with an increase in vapor pressure

• straightens out with an increase in vapor pressure

Fluid expansion is a way to sense temperature change.

• True

• False

The most popular type of bimetal element used for temperature control of a gas hot water heater is rod and _______________.

• tube

• strip

• coil

• plate

The heat anticipator in the thermostat control circuit in the heating mode is active when the ____.

• heating contact is open

• heating contact is closed

• fan switch is open

• fan switch is closed

The heater in the thermostat control circuit in the cooling mode is active when the ____.

• cooling contact is closed

• fan switch is open

• fan switch is closed

• heating contact is open

The cold anticipator is wired in ____ with the mercury bulb cooling contacts and is energized during the off cycle.

• a. series

• b. parallel

• c. sequence

• d. opposition