Water heater clacking....

[mrcaptainbob]

Okay, the 2nd floor laundry plumbing is finished. Yes...Hooray and and all that. Now there's a banging as if pipes are bumping. Traced it to the water heater! Every change in water pressure will cause it to rattle. If a faucet downstairs is cracked, it rattles and will also rattle when the well pump kicks on as well as off. Could it be the cold and hot water check valves in the tank top?

[HayZee518]

why do you have check valves in your water heater lines? a mechanical "swinging gate" check valve will rattle a little at low flow, a ball type will vibrate due to water pressure lifting the ball off its seat against a spring.

[canoebuilder]

If you have check valves in water lines it very well could be then chattering, but I don't know why you would have the need for check valves in domestic water lines.?????
Another banging sound not, just a rattle, could be due to undersize water supply lines on long runs of pipe.
To solve this you may want to install "shock absorbers" to take the noise out. I have never had to install one in a domestic but in many reseraunts or condos where the run is over 100 ft it is nessercery.
Gerry

[mrcaptainbob]

Are there not check valves in the inlet/outlet ports of the eater heater? What are the red and blue plastic inserts for?

[canoebuilder]

These are only to insure you hook up the cold water to the Blue and the Hot water line to the red.
Gerry

[HayZee518]

quote/ These are only to insure you hook up the cold water to the Blue and the Hot water line to the red/
The blue tube is a "dip tube" and goes all the way to the bottom of the tank. If you'll notice on a gas fired hot water heater the valve assembly is mounted at the bottom, not only because that is where the burner is located but the temp sensor which goes through the tank is there also.

[canoebuilder]

Absolutely right this dip tube creates what is known around here as a Hartford Loop.....By bringing in the cold water to the bottom of the tank the hot water in the tank can not migrate into the cold water pipe.
Gerry

[mrcaptainbob]

How about those heat traps? How do they work? Are they mechanical? This noise is bothersome and is most definately coming from inside the tank.

[canoebuilder]

Guess I do not know what you mean my "heat Trap"
Any evidance of water leaking around base of water heater? Air getting into the glass jacket could get the water to boil but in a 100% closed system the water would have to get way to hot to boil.
If your dealing with an electric water heater, you may have a heating element gone hay-wire and over heating...try turning the temp down and see if the problem doesn't help.
Gerry

[HayZee518]

Propane and Natural gas heaters over time develop a scale inside the tank especially at the bottom. If not flushed on a regular basis this scale builds up and may trap air inside - like a bubble - when heated these bubbles expand from the heat and may pop causing noise. The gas burner heats the bottom of the tank much like a tea kettle. Hot water rises to the bonnet and sits there waiting to be used. I don't know what canoebuilder means by the element going haywire. It's either good or bad no in between. The element is a calrod unit. a copper or stainless tube filled with a refractory sand with a nichrome wire [element] inside. the element needs to be fully covered by the water to function otherwise it will always burn up.