Water heater flues can be very handy if you have a water heater in a house with an air conditioner.
They are great for cleaning and replacing leaking water pipes and they are great to have in your house for emergencies.
They can also be used as a heat source if the air conditioners are not working.
However, if the water heater is being used for heating, they are not recommended to be used for this purpose.
They may leak or break down due to condensation on the water, and that can be dangerous if you don’t have a leak detector.
Flues also leak water, which can lead to a serious fire hazard.
You can find flues that fit a specific size and are labeled for different use cases.