I have a natural gas water heater that is 6 years old & we do not soften our water. After we use hot water and the heating cycle begins our water heater starts knocking, this began slowly and has gotten worse over the years. It did not do it at first. Is there anything I can do? Is there any way to avoid this problem if I get a new water heater? Thanks
Knocking is the result of steam expanding out from a dirt pocket into surrounding water. The steam bubble collapses making noise as the water strikes. Frequent draining of dirt from the bottom of the tank and reducing hardness may slow recurrance in a new water heater.
This will not occur in a water tank heated by boiler water as there is no direct flame to produce steam.