Gas Fitter Practice Test

When venting a gas-fired appliance into a chimney serving a solid fuel appliance, how should the vent be installed?

1. Through a separate flue opening above the other appliance's flue pipe

2. Through a separate flue opening below the other appliance's flue pipe

3. Through a job fabricated branch fitting within 30 inches

4. Through a field fabricated branch fitting within 60 inches

The correct answer is: Through a separate flue opening above the other appliance's flue pipe

The correct approach for venting a gas-fired appliance into a chimney that also serves a solid fuel appliance is to install the vent through a separate flue opening above the other appliance's flue pipe. This method is critical for maintaining safe combustion and venting efficiency. By venting the gas appliance above the solid fuel appliance's flue pipe, you ensure that the gases produced by the solid fuel appliance rise and exit the chimney effectively without being obstructed by the gases from the gas-fired appliance. This reduces the risk of backdrafts, where combustion gases can flow back into the living space instead of exiting through the chimney. Additionally, this configuration helps prevent potential contamination of the gas appliance's combustion air and improves the overall safety of both appliances. In contrast, venting below the solid fuel appliance’s flue pipe could lead to issues with gas accumulation and insufficient draft, which are hazardous. The choices involving branch fittings within specified distances are less ideal for reasons related to proper gas flow and safety standards in venting practices.