CCN1 Meter and Controls

Question 1

What is the purpose of the Emergency Control Valve (ECV) on a domestic gas meter?

Accepted Answer

To allow the gas supply to be turned off in an emergency

Answer

To regulate the gas pressure to appliances

Answer

To measure the volume of gas consumed

Answer

To prevent backflow of gas into the mains

Question 2

A gas engineer needs to check the standing pressure at a domestic meter. What reading should they expect under normal conditions?

Accepted Answer

21 mbar

Answer

11 mbar

Answer

35 mbar

Answer

75 mbar

Question 3

What type of thermostat is designed to shut off the gas supply to a boiler if the water temperature exceeds a safe limit?

Accepted Answer

Overheat thermostat (limit thermostat)

Answer

Room thermostat

Answer

Frost thermostat

Answer

Programmer timer

Question 4

What is the function of a flame supervision device (FSD) on a gas appliance?

Accepted Answer

To shut off the gas supply to the burner if the flame is extinguished, preventing a gas escape

Answer

To adjust the flame height for efficiency

Answer

To control the room temperature

Answer

To provide ignition sparks to the burner

Question 5

What does a pressure regulator (governor) on a gas meter do?

Accepted Answer

Reduces and maintains the outlet pressure at a constant 21 mbar

Answer

Measures the volume of gas consumed

Answer

Filters impurities from the gas supply

Answer

Provides emergency isolation of the gas supply

Question 6

When checking for gas leaks at a meter connection, which method should be used?

Accepted Answer

Approved leak detection fluid (LDF) applied to joints and connections

Answer

A naked flame held close to the joint

Answer

Soapy water made from household washing-up liquid

Answer

A thermal imaging camera