This is a complimentary Service detailed by Why fund Inc. (a 501 C3 NonProfit) We thank you for her donation!
*

(1. Click the food Study set you great to learn.) (2. If you wish you can click "Print" and print the test page.) (3. As soon as you desire to take it a test...click on anyone of the tests because that that research Set.) (4. Click "Check Answers" and also it will score your test and also correct her answers.) (5. You have the right to take all the test as countless times as you pick until you get an "A"!) (6. Automated college courses created from class notes, class exams, message books, reading products from plenty of colleges and universities.)


*

NAME

Question types

Written matching Multiple choice True/False

Start with

TermDefinitionBoth

Question limit

of 67 available terms

Create brand-new test


Print test

67 True/False questions

T19. An example of a mechanical regulate is a → High press switch.

You are watching: The cold anticipator is wired in

True False Water press regulating valve." type="hidden">

41. Explain what is expected by the range of a temperature regulate or press control. → The selection of a temperature/pressure control is the difference between the cut-in and also the cut-out point.

True False

7. What is supposed by the steady-state problem with for to setup a heater anticipator? → The ignition procedure has to be shut off and also the furnace has been to run for about a minute or the heating system is fired and also operating.

True False

29. How does a thermocouple readjust with temperature change? → The bimetal warps, and also the increase in temperature is converted into voltage.

True False

T16. The difference in between the suction pressure and the compressor oil pump outlet push is → The network oil pressure.

True False

22. The two types of motor temperature sensing devices are → A safety regulate (Boiler relief valve, or a pressure-regulating valve for mechanism pressure), and an operating control (water regulating valve).

True False Bimetal and also thermistor." type="hidden">

36. Why need to a safety regulate not be readjusted if it has actually a seal to stop tampering? → The pressure manage can either open up or close on a climb in pressure, This opening and closing action can manage water or various other fluids and the pressure manage can feeling a pressure differential and be designed to open up or nearby a collection of differential contacts.

True False most safety controls are pre-set in ~ the factory and also sealed, and also should instantly reset w/o tampering." type="hidden">

18. The 3 sensing facets that can be supplied with a line-voltage thermostat space → Bimetal, bellows, and liquid filled bulbs.

True False

15. A cooling thermostat ______ on a increase in temperature. → Opens.

True False Closes." type="hidden">

8. Describe the technique a business technician have to follow when measuring the present that normally travels v a warm anticipator. → 10 turns of a cable wrapped approximately an ammeter wil offer a much more accurate reading, and also remember to division your analysis by 10.

True False

12. Low voltage is preferable for residential regulate voltages since of → A push differential control.

True False Economy, safety, more precise regulate of loved one still waiting temperature, and also because in numerous states a technician doesn't require a patent to install and also service low voltage wiring." type="hidden">

T10. A thermistor engine temperature protection machine operates by → Bimetal and also thermistor.

True False causing a circuit come open when the engine overheats." type="hidden">

T13. The pressure regulate can it is in an operating manage or → The short pressure regulate can be a safety control or an open type control.

True False A security -type control." type="hidden">

13. What is the maximum amperage typically encountered through a low-voltage thermostat? → Bimetal, bellows, and liquid fill bulbs.

True False 2A." type="hidden">

20. Why is a line-voltage thermostat an installed on an electric box that has actually conduit associated to it? → To mitigate a fire hazard.

True False

T9. Many hermetic compressors room cooled by → A press differential control.

True False Suction gas." type="hidden">

T17. The air pressure regulate on a warm pump out coil → Senses the air push drop throughout the coil to identify when that should go into defrost.

True False

35. Surname two species of water pressure control. → A safety regulate (Boiler relief valve, or a pressure-regulating valve for system pressure), and an operating regulate (water regulating valve).

True False

32. Pressures below atmospheric push cannot it is in detected. → Bellows and also Diaphragms.

True False False." type="hidden">

6. The temperature drop listed below the thermostat"s set point is described as mechanism lag. → True.

True False

T12. What is provided in part applications to sense temperature in a moving airstream? → Temperature the the bordering air.

True False Helix coil." type="hidden">

T7. What is intended by the expression "temperature of the ambient air"? → Temperature that the surrounding air.

True False

31. Name two actions that deserve to be obtained with a press change. → The pressure regulate can either open or close on a rise in pressure, This opening and closing activity can manage water or various other fluids and the pressure regulate can feeling a pressure differential and also be design to open or near a set of differential contacts.

True False

9. Describe how microelectronic or electronic thermostats handle system overshoot and also system lag. → High press switch.

True False these thermostats have constructed in microprocessors with software program that will recognize the bicycle rate, or a manufacturing facility installed thermistor wired into an electric circuit that will identify the cycle rate." type="hidden">

T11. The ax fluid involves → A liquid, a vapor, and also steam.

True False

T23. A device that senses the press in a system and then switch the sensed press signal to an electronic signal normally to be handle by a microprocessor is a → press transducer.

True False

16. What two varieties of switches room normally uncovered in the sub-base of a low-voltage thermostat? → Fan-On-Auto, and Heat-Off-Cool switches.

True False

27. How can an digital thermometer be offered in a well to obtain specific response? → Opens.

True False The fine is fastened come the steel plate therefore that warm will command both into and out of the bulb, and the fine is packed so that the probe is versus the wall of the well." type="hidden">

T18. Gas press switches → A push differential control.

True False recognize the visibility of gas pressure before gas burners are allowed to ignite." type="hidden">

37. If the differential that a motor regulate is collection too small, the motor may brief cycle. → Senses the air push drop throughout the coil to determine when that should get in defrost.

True False True." type="hidden">

T1. The warm anticipator is → An flexible resistor in a space-heating thermostat supplied to protect against a heater prematurely.

True False

2. The three kinds that switching device used in low-voltage thermostats space → typically in window AC, rated up to 20 amps, castle start and stop the compressor.

True False Mercury in a bulb, open up contacts, and contacts sealed in one inert gas." type="hidden">

43. Describe the function of a press transducer, and also give an instance of wherein one would certainly be used in the HVAC/R industry. → pressure transducer.

True False The push transducer steps pressure by convert a sensed pressure signal to an electronic signal to be handle by a microprocessor. This signal is then sent out to the input/output board to operate relays to either stop or start power consuming devices. EXAMPLE: A press transducer would be hooked as much as a compressor, in a grocery store, that runs the refrigeration/freezer system." type="hidden">

25. Define a an approach for speeding up the cooling of an open up motor. → A fan or relocating air stream have the right to be provided to speed up the cooling process.

True False

21. Why carry out motors build up heat? → electrical energy the travels in ~ the motor is intended to convert to magnetism and also perform, yet instead, few of it procedures to heat. (Inductive Reactance)

True False

40. Transforming the cut-out adjustment without changing the differential adjustment will certainly automatically adjust the cut-in setting. → True.

True False

42. If a high-pressure regulate has a cut-out the 500 psig and a cut-in that 450 psig, what would certainly be the differential the the control? → Senses the air pressure drop throughout the coil to recognize when it should go into defrost.

True False 50 psig." type="hidden">

23. What is the key precaution for an externally mounted motor temperature protector? → To protect the motor from illustration too much current.

True False To defend the motor form drawing too much current and overheating." type="hidden">

T20. An example of one electro-mechanical control is a → A push differential control.

True False High push switch." type="hidden">

14. A heater thermostat ______on a increase in temperature. → Opens.

True False

24. What is the principle of operation for most externally placed overload defense devices? → To defend the motor from illustration too much current.

True False

T21. The difference in between the cut-out and also the cut-in the a manage is the → High push switch.

True False Differential." type="hidden">

T2. A cold anticipator is → Wired in parallel through the cooling contacts.

True False A fixed resistor in a space-cooling thermostat provided to start an air-conditioning mechanism prematurely." type="hidden">

T15. The oil press safety manage is → detect the presence of gas pressure before gas burners are permitted to ignite.

True False A pressure differential control." type="hidden">

28. A temperature-sensing an equipment used in measuring air flow is the → A safety -type control.

True False Bimetal disc, or helix coil." type="hidden">

39. A change in the differential the a manage will always change the selection of the control. → False.

True False True." type="hidden">

3. What does a warmth anticipator do? → It cut off heating devices prematurely.

True False

1. Why is a low-voltage thermostat normally an ext accurate than a high-voltage thermostat? → since unanticipated thermostat cycles shows device lag and system overshoot causing bigger temperature swing. (Low voltage acts faster)

True False

T6. The cold anticipator is → A addressed resistor in a space-cooling thermostat provided to begin an air-conditioning device prematurely.

True False Wired in parallel v the cooling contacts." type="hidden">

T8. What space two types of engine temperature protection devices? → Bimetal and thermistor.

True False

33. Name one duty of a low pressure control. → A safety regulate (Boiler relief valve, or a pressure-regulating valve for device pressure), and an operating regulate (water regulation valve).

True False The low pressure manage can it is in a safety manage or one open type control." type="hidden">

5. Define system overshoot when taking care of thermostats. → The temperature rise in a room (room temperature) above the set point of a thermostat.

True False

T3. The heating thermostat _____ ~ above a climb in temperature. → Opens.

True False

34. What is true that a high-pressure control? → that protects the compressor from high pressures.

True False

44. List two advantages an digital oil safety controller has actually over a mechanical, bellows-operated oil safety controller. → Economy, safety, much more precise regulate of family member still wait temperature, and also because in plenty of states a technician doesn"t need a patent to install and also service short voltage wiring.

True False that eliminates capillary tubes, thus offering it a much less chance the a refrigeration leak, and the digital clock and also circuitry space much an ext reliable." type="hidden">

10. Describe how a bimetal functions. → The controls room arranged to apply much more or much less pressure to the sensing facet that varies the temperature range.

True False

38. A change in the differential setup will automatically readjust the cut-in point of the control. → True.

True False False." type="hidden">

T14. A switch the detects air motion in a duct with electrical heat is a → Sail switch.

True False

4. What go a cold anticipator do? → It cut off heating tools prematurely.

True False that starts the system a few minutes early on to enable the mechanism to reach complete capacity come anticipate the volume lag." type="hidden">

19. What is the preferably amperage usually encountered in a line-voltage thermostat? → 25A.

True False

T5. The low-voltage thermostat passes power from ____ to the loads in the regulate circuit. → To reduce a fire hazard.

True False A transformer." type="hidden">

11. What component procedures down the voltage come the low voltage value? → The step down transformer.

True False

30. Name two approaches to transform pressure changes into action. → The short pressure manage can it is in a safety manage or one open form control.

True False Bellows and Diaphragms." type="hidden">

26. Explain two techniques for cooling an overheated compressor. → A security -type control.

True False Cooling by air, cooling by water, or time." type="hidden">

17. Once is a line-voltage thermostat used? → that starts the device a couple of minutes beforehand to allow the device to reach complete capacity come anticipate the capacity lag.

See more: Closest Airport To Starkville, Mississippi, Us, Transportation

True False normally in window AC, rated up to 20 amps, castle start and also stop the compressor." type="hidden">

T22. A regulate adjustment that provides for the exactly minimum and also maximum pressure or temperature is the → Closes.