deliming solvents
A. O. Smith recommends the use of UN•LIME for deliming. UN•LIME is a patented food grade acid which is safe to handle and does not create the harmful fumes which are associated with other products.
UN•LIME may be obtained from your dealer, distributor or A. O. Smith Product Service Division. Order Part Number 9005416105, 1 gallon, packed 4 gallons per case or Part Number 9005417105, 5 gallon container.
NOTE: Un•Lime is not available for use in Canada.
Hydrochloric base acids are not recommended for use on glass lined tanks.
Observe handling instructions on label of product being used.
tank Cleanout Procedure
The following practices will ensure longer life and enable the unit to operate at its designed efficiency:
1.Once a month the heater should be flushed. Open the drain valve and allow two gallons of water to drain from the heater. Inlet water valve should remain open to maintain pressure in tank.
2.A cleanout opening is provided for periodic cleaning of the tank. Gas must be shut off and heater drained before opening cleanout.
To clean heater through cleanout opening, proceed as follows:
3.Drain heater.
4.Remove outer cover plate from lower side of heater jacket.
5.Remove six (6) hex head screws securing tank cleanout plate and remove plate.
6.Remove lime, scale, or sediment using care not to damage the glass lining.
7.Inspect cleanout plate gasket, if new gasket is required, replace with part no. 9004099215.
8.Install cleanout plate. Be sure to draw plate up tight by tightening screws securely.
9.Replace outer jacket cover plate.
In some water areas the sediment might not be removed by this method and may result in the water heater making rumbling or boiling noises. To dissolve and remove these more stubborn mineral deposits, A. O. Smith UN•LIME Professional Delimer should be used.
DELIMING USING FLO-JUG METHOD
UN•LIME in the 5 gallon size is recommended for deliming of all models. Contact your local A.O. Smith dealer, distributor or, A.O. Smith Water Products Company:
Telephone: (800)
Fax: (800)
Website: www.hotwater.com/parts
Prepare the Water Heater
To delime the water heater using the
Explosion Hazard
Flammable hydrogen gases may be present.
Keep all ignition sources away
from faucet when turning on hot water.
Do not smoke or have open flame or sparks in vicinity of heater. Do not mix UN•LIME with other chemicals. Do not allow contact with magnesium, aluminum or galvanized metals.
Chemical Hazard
• Product contains phosphoric acid.
• Keep out of reach of children.
• Use rubber or neoprene gloves.
Contains phosphoric acid. In case of external contact, flush with cool water. If irritation persists, get medical attention. If swallowed, give 1 or 2 glasses of water or milk and call physician.
Get immediate medical attention for eyes. Keep out of reach of children.
NOTE: THE USE OF RUBBER OR NEOPRENE GLOVES IS RECOMMENDED, ESPECIALLY IF YOU HAVE ANY OPEN SORES OR CUTS TO AVOID UNNECESSARY IRRITATION OR DISCOMFORT.
1.Turn off fuel and/or power supply to heater. Also, turn off power to any electrical device or equipment, which is attached, or part of the system.
2.Open hot water side of faucet closest to heater and allow water to run until it is cool enough to handle safely.
3.Close cold water inlet valve to heater.
4.Connect hose to drain valve at bottom of heater and start draining heater into suitable floor drain area.
5.Remove relief valve while heater is draining. NOTE: Do not replace relief valve until deliming is completed. Relief valve opening will also act as a vent in case of possible contact between the delimer and the anode rod(s), which may produce flammable
6.If relief valve appears to be
7.If heater does not drain completely after a reasonable length of time, turn off the main water supply valve to stop water from entering the tank due to a
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