Kyung Dong Navien Co. Ltd, South Korea

A kit installed on the tankless water heaters and boilers to convert them from natural gas to propane can cause the unit to produce excessive amounts of carbon monoxide, posing a risk of carbon monoxide poisoning to consumers.

An unstable connection can cause the water heater's vent collar to separate or detach if pressure is applied. A detached vent collar poses a risk of carbon monoxide poisoning to the consumer.