WorksheetsLB H Thermo-electric Valve Control System Quiz
Total questions: 53
Worksheet time: 27mins
What is the primary function of a thermocouple in a thermo-electric valve control system?
To heat the pilot flame
To produce a small electric current
To cool the gas valve
To increase the gas flow
What is the typical voltage produced by a thermocouple?
5V
15V
15mV
150mV
Why should a thermocouple not be tested open circuit?
It will produce a low output reading
It will produce an artificially high output reading
It will not produce any reading
It will overheat
What happens when the control knob is in the "Off" position ?
Gas flows to the pilot burner
Gas flows to the main burner
No gas flows
Gas flows to both burners
What is the recommended maximum drop out time for a central heating boiler ?
60 seconds
90 seconds
80 seconds
70 seconds
Which appliance has a maximum drop out time of 90 seconds?
Cooker – ovens
Space heaters
Central heating boiler
Combi and multi-point water heaters
What should be done if a thermocouple system fails to shut down within the maximum times shown?
It must be regarded as Immediately Dangerous and repaired or replaced.
It should be ignored.
It should be checked again after 10 minutes.
It should be left as it is.
What is the purpose of an overheat thermostat in central heating boilers?
To shut the appliance down if the boiler thermostat fails.
To increase the temperature of the water.
To reduce the noise of the boiler.
To improve energy efficiency.
What is the function of the overheat thermostat in an interrupted thermo-couple system?
To increase electrical resistance
To detect an overheat condition and trip the circuit
To provide continuous electrical input
To enhance the flame failure valve
What happens when there is a lack of oxygen affecting the combustion air in an appliance with an Atmospheric Sensing Device (ASD)?
The appliance will continue to operate normally
The appliance will shut down automatically
The appliance will increase its temperature
The appliance will require manual intervention
What is the primary purpose of Oxygen Depletion Systems in gas appliances?
To increase the flame size
To detect and respond to low oxygen levels
To enhance the color of the flame
To reduce the appliance's energy consumption
What is the primary function of a spillage detector in appliances?
To increase air intake
To detect spillage of combustion products
To enhance heat exchange
To regulate water temperature
Where is a spillage detector typically located on open flue appliances?
On the water heater
On the combustion chamber
On the draught diverter
On the heat exchanger
What happens when the sensor in a spillage detector heats up?
It increases air intake
It shuts off the appliance
It opens the flue
It decreases combustion
What is a common use for gas taps and valves?
Water filtration
Gas control in cookers and fires
Air conditioning
Electrical wiring
What is a necessary precaution when dismantling and regreasing gas taps?
Use a large amount of grease
Over tighten the screws
Ensure the tapered plug is in the correct orientation
Ignore leakage checks
What happens if the flame is extinguished in a liquid expansion flame supervision device?
The valve opens to high gas supply
The vapour pressure increases
The valve closes the main gas supply
The phial expands
What is the function of the phial in a liquid expansion flame supervision device?
To cool the bellows
To contain a volatile vapour or liquid
To block the gas valve
To ignite the burner
Where is the temperature sensing phial normally positioned in an oven?
Directly above the burner
Inside the burner
In the top of the oven
Below the oven
What happens to the bellows when the oven reaches its set temperature?
The bellows expand
The bellows contract
The bellows remain unchanged
The bellows burst
What is the purpose of the maintenance rate in an oven?
To increase the oven temperature
To maintain the oven temperature at a steady level
To decrease the oven temperature
To turn off the oven
What occurs when the oven cools down?
The bellows expand
The main gas valve closes
The bellows cool and retract
The oven turns off
What is the primary function of electric thermostats in a central heating boiler?
To increase water pressure
To control water flow temperature
To regulate air flow
To monitor gas levels
How does the phial in an electric thermostat function?
It uses a magnetic field
It uses a liquid expansion mechanism
It uses a digital sensor
It uses a thermal resistor
What happens when the boiler reaches the set temperature?
The phial contracts
The micro-switch closes
The bellows expand
The burner ignites
What is the role of zero governors in gas appliances?
To increase gas pressure
To control the gas/air ratio
To monitor temperature
To regulate water flow
What is the function of the main spring in a zero governor?
To increase outlet pressure
To act on the main diaphragm
To adjust the gas throttle rate
To control the air inlet
Which component in a zero governor is responsible for adjusting the gas flow rate?
Compensating diaphragm
Impulse tube
Gas throttle rate adjuster
Air inlet
What happens when the lid is closed in a safety shut off device?
Gas flows to the burners
Gas cannot flow to the burners
The valve opens automatically
The reset switch is activated
Which type of safety shut off device uses a cam operated valve?
Reset type
Switch back system
On/Off cam operated valve
Manual valve
What principle do flame rectification systems use to detect a flame?
Flame conduction and rectification of a small electric current
Direct current flow through the flame
Heat detection through infrared sensors
Optical flame detection
What happens if the flame fails in a flame rectification system?
The main gas valve remains open
The system continues to operate normally
The signal stops and the main gas valve closes
The system switches to a backup power source
What is the role of the electronic control box in a flame rectification system?
To provide a backup power source
To hold the main gas valve open while receiving the rectified AC signal
To detect the temperature of the flame
To measure the gas pressure
What is the function of solenoid valves in gas systems?
To measure gas pressure
To directly turn a gas supply on and off
To detect gas leaks
To regulate gas temperature
What is one of the functions of a multi-function valve in a gas boiler?
Water filtration
Pilot adjuster
Air conditioning
Electrical wiring
Which component is NOT typically included in a multi-function valve?
Solenoid valve
Flame protection device
Water pump
Soft light device
What should be done if a multi-function valve is faulty?
Repair it in the field
Replace it with a new one
Ignore the fault
Use a different model
What is the primary function of pressure governors (regulators)?
To increase upstream pressure
To maintain a constant downstream pressure
To reduce gas consumption
To enhance gas flow speed
How is the outlet pressure adjusted in a pressure governor?
By turning the screw counter-clockwise
By changing the diaphragm material
By adjusting the screw on top of the diaphragm spring
By increasing the gas flow
What happens when the downstream gas pressure drops?
The diaphragm moves down
The valve closes
The diaphragm spring compresses
The valve opens to allow more gas through
What is the function of the impulse pipe in a compensated regulator?
To adjust the screw
To vent air to the atmosphere
To connect the main diaphragm to the gasway
To fit on the outlet of the main diaphragm
What is the role of the compression spring in a compensated constant pressure regulator?
To control upstream pressure
To control downstream pressure
To adjust the breather hole
To connect the impulse pipe
What happens when the gas is turned off and the pipe system is empty in a compensated regulator?
The spring will expand
The diaphragm will rise
The spring will act down on the diaphragm
The valve will open automatically
What is the purpose of the compensating diaphragm in a compensated regulator?
To increase the gas flow
To compensate for pressure differences
To adjust the screw
To vent air to the atmosphere
What is the defined pressure range for medium pressure regulators?
50mbar to 1bar
75mbar to 2bar
100mbar to 3bar
25mbar to 1.5bar
What is the primary function of catalytic panels in domestic flueless fires?
To increase the temperature of combustion gases
To reduce CO products in combustion gases
To enhance the color of the flame
To increase the lifespan of the appliance
What is a key benefit of using flame rectification technology?
It increases the size of the flame
It reduces the need for regular maintenance
It reduces inefficiency due to boiler cycling on/off
It enhances the color of the flame
What is the role of a wet and dry pocket thermistor in boiler systems?
To control the color of the flame
To measure the water level in the boiler
To accurately measure and control temperature
To increase the pressure in the boiler
How does a variable speed pump save electrical energy?
By increasing the water temperature
By varying the speed of the circulating pump based on heat demand
By reducing the size of the boiler
By increasing the pressure in the system
What is a requirement of the GS(I)UR's regarding proving air flow?
The gas supply must be isolated from the air supply
The system must be interlocked with the gas for combustion
The air flow must be increased to maximum levels
The system must operate without any sensors
What is the purpose of flue duct monitoring systems ?
To monitor the presence of CO in the chimney/flue system
To increase the temperature of the flue gases
To reduce the noise from the flue system
To enhance the aesthetic appearance of the chimney
When replacing parts or controls, what should not be relied upon according to the document?
External appearance
Manufacturer's warranty
Installation manual
Customer reviews
What information is essential when ordering spare parts?
Type of gas the appliance operates on
Color of the appliance
Year of manufacture
Weight of the appliance