Gas Appliance Operating Pressure Quiz

Which of the following is NOT a reason for the operating pressure at a gas appliance inlet being excessively low?

• Incorrectly set primary meter regulator.

• Over-sized installation pipework between the meter and the appliance.

• Undersized installation pipework between the meter and the appliance.

• Partial blockage in the installation pipework between the meter and the appliance.

What may be the effect of excessive burner operating pressure on a natural gas appliance?

• Flame lift off.

• Flame light back.

• Increased appliance efficiency.

• Improved combustion efficiency.

On a fanned flue boiler, what will the safety control circuitry prove prior to allowing the fan to run?

• The flame rectification circuit is sensing a flame.

• The fan is delivering an adequate draught / pressure.

• The flue flow sensor is in the 'no flow' or 'no air' position.

• The burner has modulated to give the correct heat output.

To ensure that any appliance can operate safely should the operating pressure on the outlet of an emergency control valve (ECV) drop to 19 mbar, the pressure absorption allowed across a primary meter installation, under maximum flow conditions, shall not exceed:

• 1 mbar

• 4 mbar

• 5 mbar

• 8 mbar

The outlet pressure on a low pressure primary meter installation is designed to be nominally 21 mbar, this pressure will fluctuate around the set point of the regulator dependant on the gas flow rate. The acceptable range of operating pressures in relation to flow rates is:

• 20 mbar, 22 mbar

• 22 mbar, 20 mbar

• 19 mbar, 23 mbar

• 23 mbar, 19 mbar