TECHNICAL BULLETIN

• Rumbling
• Crackling
• Popping

With the advent of high input and larger storage tanks in both commercial and residential heaters, deliming has become a necessity of modern maintenance. Lime (CaCO₃), is the most notable factor when discussing water hardness. Lime is present in every water system to some degree across the United States. Since lime is inversely soluble [the more you heat, the more lime comes out], higher usage, excessive hardness, and increased heating surface can lead to a high incidece of “limed-up” heaters.

Symptoms often include a popping of water trapped under lime deposits or the sizzling of water trapped next to elements, boiling it to steam. 

Treatment of a “limed-up” heater is relatively simple. Since CaCO₃ is a base, the easiest way to disolve it so it can be flushed from the heater is with an acid. The most commonly used is phosphoric acid at a food grade level. Standard household cider vinegar may also be used. Follow the steps in the “SOLUTION” section of this bulletin.

Any well stocked plumbing supply house should have a deliming soultion suitable for use in potable water systems available.

The directions on the product should be followed explicitly.

1. Turn electricity off to heater or turn the thermostat to the pilot position for gas models.
2. Turn off the cold water supply to the water heater. (Normally, a valve on the right side before the water heater).
3. Open the hot water faucet in a bathtub or sink to relieve the pressure in the system: leave it on.
4. Connect a garden hose (rated for 200°F) to drain valve located on the bottom of the water heater. Open the drain valve and let the water heater drain completely then close the drain valve.
5. Disconnect the cold-water inlet, hot-water outlet ot T & P valve and, using a funnel, pour one (1) gallon of regular household cider vinegar into the water heater. NOTE: Do not dilute with water.
6. Let vinegar set in water heater for a period of at least six (6) hours.

• After the allowed time has passed, reconnect the inlet, outlet, or T&P valve. Open drain valve and turn on the water to flush out the disolved sediment and vinegar.
• Close the drain valve.
• Fill the water heater until you get waTer coming out the faucet you opened earlier.
• Close the faucet that was opened and turn the water heater on to reheat.

NOTE: It may be necessary to repeat the