Popping noise as it cycles up. - A.O. Smith BTH-199 BTH-199 100 Gallon 199,000 BTU Cyclone Xi[REG] Commercial Gas Water Heater

either solenoid valve is closing or there is a large water hammer occurring

check for objects in the tub such as hair pin ,nail etc...

Popping sound is caused by sediment built up in bottom of tank: air bubbles get trapped when heating starts, and then they crackle, rumble etc when free.
Clean out sediment:
http://waterheatertimer.org/Clean-sediment-out-of-water-heater.html
http://waterheatertimer.org/pdf/How-to-descale-water-heater.pdf
The steps vary by type of water heater, gas or electric

If you need further help, I’m available over the phone at https://www.6ya.com/expert/gene_9f0ef4df2f9897e7

Describe the noise

odd noise like popping or singeing fire....clicking noises.....sounds like you have a water leak putting out the pilot.......or your thermo coupling is bad....or the noise is the tank full of calcium buildup and that will make noises when the burner is on

Sounds like an old water heater, full of rust at bottom. maybe coming to end of its life. Think new if over 7 years old. Did you replace anode rod? Probably shot also. Good Luck...

That typically means the softener is in a regeneration cycle. When the valve is switching cycles it quite frequently will have the noise you describe. The regeneration cycle should be set for 2am.
RJ

What is probably happening is that you have a build up of minerals on inner tank lining and when unit is heat it expands the tank and the deoosits at a different rate which is what is causing the popping noise.
I would turn power off to your heater and hook a garden hose on to drain valve.Route hose to safe area as the water being drained will be hot. Open drain valve and see if you can get it draining good.If it is then shut off water supply to heater and open hot side of faucet nearby to prevent vacumn from slowing down draining. I would drain as much as I could then close drain valve and faucet and refill tank. I would do this several times to try to get all sediment flushed out.Hopefully this will help with your noise and make your heater last longer and work more effceiently. Good luck and thank you.

There are several different things the sound could be. If it is a popping noise it could be from the sediment inside the water heater as it is heating. It could also be noise(bang) from the water pipes having excessive pressure. If the water heater is gas it could be the noise from the burner when in operation or gas regulator vibration. Need a better description of the noise to be more helpful.

Sounds like water is over heating. (thermostat).Is water real hot.?