Which schematic diagram represents a heating thermostat?
NC temperature-actuated switch
NO temperature-actuated
NC liquid level-actuated switch
NO liquid level-actuated switch
What are the two types of electrical diagrams used in the heating and cooling industry?
Power and control
Schematic and wiring
Power and wiring
Control and power
What is best use to demonstrate how electrical circuits works?
Schematic diagram
Wiring diagram
Power source diagram
Control diagram
Which diagram is used to find the physical location of a component?
A device that reacts to changes in a variable-condition is referred to as?
A relay device
An igniting device
A load device
A controlling device
An example of a load device is
Thermostat
Limit switch
Fan switch
Gas valve
What is an example of a limit safety control device?
High limit switch
High temperature switches
Low-pressure switch
All the above
Power supplies if 24 volts, are used to operate what part of the system?
The power circuit
The control circuit
The protection circuit
The thermocouple circuit
When does a gas fired furnace in a single-dwelling require a disconnect switch?
Always
Not required
As required by section 26 in the CEC
As required by section 16 in the CEC
Is a residential furnace allowed to have a light in the furnace room on its supply circuit?
Yes
No
What section of the CEC deals with the control circuit wiring?
Section 16
Section 26
Section 28
Section 32
What are the most commonly used types of temperature-sensing devices?
Bimetal temperature-sensing elements
thermistors
RDT’s
Pyrometer’s
Which type of temperature-sensing device is best used to operate large snap action contacts such as line voltage thermostats?
Strip type bimetal temperature-sensing element
Spiral type bimetal-sensing device
Liquid bulb type
Bellows type temperature-sensing devices
What type of temperature sensing device is especially suitable for pipes or tanks
Bellows type
Thermocouple
Thermistor
A thermocouple generates a typical voltage of?
20mv
30mv
40mv
50mv
A thermopile generates a typical voltage of up to
500mv
600mv
700mv
800mv
Which of these two devices has a constant temperature to resistance ratio?
RTD
The types of contacts used in thermostats are?
Mercury
Spring activated, snap-action, exposed
Glass-enclosed, magnet and armature snap-action
In a heating thermostat the anticipator has what type of connection with the contacts?
Series connection
Parallel connection
Combination connection
Compound connection
In a cooling thermostat the anticipator has what type of connection with the contacts?
Where is the best location for a thermostat?
On an inside wall
On an outside wall
Under the HVAC
Directly opposite the heat flow
The usual setting of a high limit switch for a furnace is?
70-80 degrees C
80-100 degrees C
90-130 degrees C
80-120 degrees C
When not connected to the power supply, the position of the thermocouple relative to the pilot flame should be adjusted to read?
Open circuit test of 26-32 mv
Closed circuit test of 26-32 mv
Open circuit test of 7.5-15 mv
Closed circuit test of 7.5-15 mv
What type of control switch resets when the temperature drops 11 degrees below the set point?
High limit/ fan control switch
Thermostat actuator switch
High limit main gas valve switch
Summer switch
What device is represented by the words COMP in a legend?
Contactor
Compressor motor
Condenser fan motor
Indoor fan motor
What type of thermostat is used for a basic heating system?
Two wire
Three wire
Five wire
Seven wire
Which type of thermostat will have an on-off-auto switch?
Which type of thermostat is used for combination heating and cooling units?
Which type of thermostat is required for two stage heat and two stage cooling?
When do you connect RH and RC together in a five wire thermostat
When one control transformer is used
When two or more control transformers are used
