Temperature-Sensing and Control Devices Flashcards
What is a bimetal strip element in a thermostat?
It consists of two different metals, one of which has a high rate of thermal expansion compared to the other
Which type of temperature-sensing device would be suitable for operating a large snap-action contact?
a bellow type
What would be the best type of temperature-sensing devices for monitoring the temperature in a pipe of a tank?
liquid bulb
Which voltage do thermocouples typically generate?
up to 30 mV
A thermopile generates a typical voltage of up to _____ mV
800
What is the purpose of a thermocouple?
to prove the presence of a flame
What device has a constant temperature to resistance ratio?
resistance temperature detector (RTD)
What is the usual setting of a high limit switch in a furnace?
80-120 degrees Celsius
What is the typical temperature setting for a Fan ON switch in a furnace?
49 - 60 degrees Celsius
What is the typical temperature setting for a Fan OFF switch in a furnace?
32 - 38 degrees Celsius
A heating thermostat usually has a _____ connection with the main gas valve
series
What are the three types of contacts used in thermostats?
mercury, spring activated, glass enclosed
In a heating thermostat, the anticipator has a ____ connection with the contacts
series
In a cooling thermostat, the anticipator has a ____ connection with the contacts
parallel
What is the purpose of heat/cool selector switch on a heating and cooling thermostat?
to select heating or cooling function only
