Technical Standards and Safety Authority (TSSA) G3 Practice Exam

For a system supplying an appliance with rated input under 400,000 Btuh, where may the supply line be purged?

1. At the main burner

2. At the drip pocket of the appliance

3. Into the combustion chamber

4. At a readily accessible burner

The correct answer is: At a readily accessible burner

In the context of purging a gas supply line before lighting the appliance, the correct option allows for the safe and effective removal of any air or gas mixtures to prevent combustion issues. The most appropriate location for purging the supply line is at a readily accessible burner. This is because purging at this location permits easy access to control the flow of gas and ensure that any remaining air is expelled before the burner is ignited. This method also allows for observation and immediate shut-off if there are any issues during the purging process. By using a burner that is easily accessible, technicians can safely monitor the situation and make adjustments as necessary to establish proper combustion conditions. The other options present various risks or practical challenges. For example, purging at the main burner or the drip pocket may not provide the same level of control and could lead to complications if the burner is not designed for that purpose. Purging directly into the combustion chamber is potentially hazardous and could lead to unsafe conditions. Thus, purging at a readily accessible burner ensures that safety protocols are adhered to and that the operation can be managed effectively.