What should a technician do if a natural gas furnace is found to have a defective heat exchanger?

When a technician discovers that a natural gas furnace has a defective heat exchanger, the most appropriate action is to inform the homeowner and turn off the gas supply. This step is crucial for a couple of reasons.

First, a defective heat exchanger can lead to potentially dangerous situations, including carbon monoxide leakage into the home, which poses a significant health risk to the occupants. By turning off the gas supply, the technician ensures that no further gas is being fed into the furnace, minimizing the risk of gas accumulation or a catastrophic failure.

Second, informing the homeowner allows them to be aware of the situation and take necessary precautions, such as avoiding use of the furnace until it is repaired or replaced. This communication ensures that the homeowner can make informed decisions regarding their safety and the heating needs of their home.

While repairing or replacing the heat exchanger or the entire furnace may be necessary for long-term resolution, those actions would typically occur after the immediate safety concerns are addressed and the homeowner is informed. These options would involve further assessment of the system and should not be conducted while the furnace is in a compromised state.