Thermostats Flashcards
True or False
A thermostat can control the temperature of a conditioned space or a process
true
T or F
“Manual changeover” is the terminology applied to the movement of mercury in a sealed contact type thermostat
false
________ __________ is the changing from the heating mode to cooling mode (and vice versa) by thermal means only
automatic changeover
A ________ is an instrument which responds to changes of temperature and which directly or indirectly controls temperature
thermometer
A bimetal is usually made up of _____ different materials
two
A change in _______ temperature will affect a change in the ______
ambient, bimetal
T or F
“Droop” or “thermal offset” does not affect the operating control point of a thermostat
false
Two commonly used metals in the construction of bimetal temperature sensing elements are _____ and ______
brass and invar
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
detent snap
T or F
Anticipation is the addition of heat to thermostat contacts
True
T or F
Heating cycle anticipators are energized during the heating “off” cycle
false
T or F
Range is the difference between the thermostat min and max operating points
true
The difference between cut-out and cut-in is referred to as the _________
differential
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
c) anticipation
The setting of the anticipator in the heating cycle must match the ______ rating
current
T or F
All thermostats should be level
True
T or F
The best thermostat location in a residential installation is eight feet above the floor
False
Always use _______ wiring when installing a thermostat
coloured
The most important step in installing a thermostat is ______
location
The final thermostat should be free of _______ that might make the contacts _____
vibration, close
Thermostat installation should be about ___ feet above the floor
5 feet
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
True
In a heating system, a thermostat bimetal exposed to a false source of _____ may cause an extended “on” cycle
cold
A _____ ______ is a good tool to use to clean exposed contacts
match cover