Thermostats Flashcards

1
Q

True or False

A thermostat can control the temperature of a conditioned space or a process

A

true

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2
Q

T or F

“Manual changeover” is the terminology applied to the movement of mercury in a sealed contact type thermostat

A

false

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3
Q

________ __________ is the changing from the heating mode to cooling mode (and vice versa) by thermal means only

A

automatic changeover

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4
Q

A ________ is an instrument which responds to changes of temperature and which directly or indirectly controls temperature

A

thermometer

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5
Q

A bimetal is usually made up of _____ different materials

A

two

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6
Q

A change in _______ temperature will affect a change in the ______

A

ambient, bimetal

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7
Q

T or F

“Droop” or “thermal offset” does not affect the operating control point of a thermostat

A

false

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8
Q

Two commonly used metals in the construction of bimetal temperature sensing elements are _____ and ______

A

brass and invar

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9
Q

Most exposed type contacts being used today have a magnet added. The magnet provides the _____-____ action making it possible for the electrical contacts to open and close quickly and precisely

A

detent snap

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10
Q

T or F

Anticipation is the addition of heat to thermostat contacts

A

True

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11
Q

T or F

Heating cycle anticipators are energized during the heating “off” cycle

A

false

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12
Q

T or F

Range is the difference between the thermostat min and max operating points

A

true

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13
Q

The difference between cut-out and cut-in is referred to as the _________

A

differential

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14
Q

BY adding artificial heat to the thermostat bimetal an increased rate of response by the thermostat is available through a reduced differential is referred to as _________

a) minimum interlock
b) differntial
c) anticipation
d) droop

A

c) anticipation

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15
Q

The setting of the anticipator in the heating cycle must match the ______ rating

A

current

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16
Q

T or F

All thermostats should be level

17
Q

T or F

The best thermostat location in a residential installation is eight feet above the floor

18
Q

Always use _______ wiring when installing a thermostat

19
Q

The most important step in installing a thermostat is ______

20
Q

The final thermostat should be free of _______ that might make the contacts _____

A

vibration, close

21
Q

Thermostat installation should be about ___ feet above the floor

22
Q

T or F

Low voltage (24v) wiring should be thermostat cable or equivalent with single leads of 18awg coloured coded wire as the minimum size for runs under 50 Ft

23
Q

In a heating system, a thermostat bimetal exposed to a false source of _____ may cause an extended “on” cycle

24
Q

A _____ ______ is a good tool to use to clean exposed contacts

A

match cover

25
A differential that is too ______ may cause a system to short cycle
small
26
When troubleshooting a thermostat for a condition where the system short cycles look for: a) false source of heat or cold b) check differential c) system oversized d) all of the above
d) all of the above
27
If the system stays the "ON" cycle too long, check a) system undersized b) false source of heat or cold c) incorrect anticipator setting d) all of the above
d) all of the above