Gas Fitter Practice Test

Where should a backflow preventer used in a boiler system be located?

1. Over flow line connected to the drain

2. Return line close to the boiler

3. 1/4" line connecting the boiler and cushion tank

4. Make up water line to the system

The correct answer is: Return line close to the boiler

The correct placement of a backflow preventer in a boiler system is on the return line close to the boiler. This is significant because it helps protect the boiler and the entire water system from contamination and backflow of potentially hazardous substances. When the backflow preventer is situated near the boiler, it can effectively control any reverse flow that could carry harmful pollutants back into the potable water supply. By positioning it in this location, it ensures that if there is a drop in pressure or a disruption in the system, the backflow preventer will effectively prevent any reverse flow of water from the boiler into the supply line. This is crucial for maintaining the safety and integrity of the water system. In contrast, placing the backflow preventer on the overflow line, or in other locations such as the cushion tank line or the make-up water line, would not provide the same level of protection. Those alternatives may not effectively prevent contamination effectively as they could still allow potentially harmful substances to reach the boiler or other parts of the system. Thus, the best practice is to install the backflow preventer where it can monitor and control the flow directly related to the boiler’s operation.