AC CONTROLS (TUESDAY MORNING ) TEST |ACTUAL COMPLETE EXAM QUESTIONS AND CORRECT ANSWERS |A GRADE.
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AC CONTROLS
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AC CONTROLS
AC CONTROLS (TUESDAY MORNING ) TEST |ACTUAL COMPLETE
EXAM QUESTIONS AND CORRECT ANSWERS |A GRADE.
AC CONTROLS (TUESDAY MORNING ) TEST |ACTUAL COMPLETE
EXAM QUESTIONS AND CORRECT ANSWERS |A GRADE.
AC CONTROLS (TUESDAY MORNING ) TEST |ACTUAL COMPLETE
EXAM QUESTIONS AND CORRECT ANSWERS |...
AC CONTROLS (TUESDAY MORNING ) TEST |ACTUAL COMPLETE
EXAM QUESTIONS AND CORRECT ANSWERS |A GRADE.
Which component uses the properties of AC induction to step up or
step down voltage for particular HVACR applications? - ANSWER-
Transformer
The purpose of a standard control transformer is to - ANSWER-
Reduce the line voltage to 24 volts for HVACR control systems
What is the maxiumum safe secondary current for a 40 VA
transformer that has a primary voltage of 240V and a secondary
voltage of 24 V? - ANSWER-Maximum Output = VA Divided by
Secondary Voltage (Output Voltage) = 40VA/24V = 1.67 amps
The standard transformer VA rating for most HVACR systems is -
ANSWER-40VA
An electrical component that stores energy when an electrical charge
is forced onto its plates is called - ANSWER-Capacitor
How does a remote bulb thermostat work? - ANSWER-An electronic
sensor in the bulb sends signals back to the thermostat.
What is the common sensing element used in an electronic
thermostat? - ANSWER-Thermistor.
Controls that use human hair for sensing are: - ANSWER-Humidistats.
Which type of thermostats provide the closest temperature controls?
- ANSWER-Electronic low voltage thermostats.
What is the purpose of the heat anticipator used in a mechanical low
voltage thermostat? - ANSWER-To reduce the temperature swing.
What is the most common form of switching used for mechanical
, thermostats? - ANSWER-Mercury bulb.
What is used as the sensing element in a mechanical humidistat? -
ANSWER-A nylon ribbon or hair.
What is the most common temperature sensing element used for
mechanical thermostats? - ANSWER-Bi-metal coil
The elctrical switching in an electronic thermostat is often done by: -
ANSWER-Resistors.
Compared to mechanical thermostats, digital thermostats - ANSWER-
Maintain closer temperature control.
The thermostats on most residential air conditioning systems are: -
ANSWER-Low voltage thermostats.
Line voltage thermostats can usually switch: - ANSWER-15 amps
Line voltage thermostats normally operate on: - ANSWER-120 volts
Low voltage thermostats normally operate on: - ANSWER-24 volts
what is the purpose of staging thermostats? - ANSWER-To allow
systems to operate at reduced capacity.
Heat pump thermostats generally require two stages of heating in
order to control: - ANSWER-The auxillery heat.
What is the switching action of a fan cycling head pressure control? -
ANSWER-Close on pressure rise for induced draft condensers, open
on pressure rise for forced draft condensers.
How can a low pressure switch be used as an operating control for a
refrigeration case? - ANSWER-Because the evaporator pressure goes
up and down with the case temperature.
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