I noticed a clicking noise coming from my water heater (50 gallon gas Richmond) near the hot water nipple when I turned on any hot water in the house. I heard click/click/click/click pause click. The sound lasted between 1-2 seconds. The noise only happened immediately after the hot water is used anywhere in the house, it didn't happen when the burners fire to heat up the water again or at any other time.
I thought I needed to drain the heater because it had not been drained since we got it five years ago. I opened a hot water tap to avoid creating a vacuum and drained the heater. It drained very slowly, about 8 gallons an hour. ( I measured it) I filled a clear gallon container and the water was lightly discolored (tinted brownish).
I did not drain the tank completely, about 30 out of 50 gallons were drained. After I refilled and reheated the tank, the noise was gone. However, today when I turn on the hot water, the noise is back. Someone suggested that it might be the hot water check valve on the nipple leading to the hot water outlet. The nipples on both sides are brass and I think the plumber might not have used check valves when he installed it. Is there such a thing as a brass check valve?
Questions: Is there something else that could be causing this noise? Did I do the right thing but not drain it enough? Was most of the mineral buildup still left in the tank? Should I drain it completely next time? Is there a faster way to drain the heater? Also, my heater has a cone valve. I was prepared to switch it out to a ball valve but ran into a problem. The cone valve was easily removed by turning it counterclockwise about 5-6 times and then pulling it off. However, the part that the valve actually fits into (also white plastic) is still attached to the heater. It has a place to fit a wrench but...more than one site said to remove the valve counterclockwise, then clockwise. It looks like I should just remove the second part counterclockwise but...? I was also told that a brass nipple would be fine, then I was told that I need a plastic coated nipple to attach the valve to the tank. Which is best?
Thanks in advance, Kenhreed
Sorry for the long post but I'd appreciate any help from anyone.