Deliming Solvents; Tank Cleanout Procedure; Deliming Using Flo-Jug Method - A.O. Smith BL-80 Instruction Manual

Lime accumulation not only reduces the life of the equipment but
also reduces efficiency of the heater and increases fuel consumption.
The usage of water softening equipment greatly reduces the
hardness of the water. However, this equipment does not always
remove all of the hardness (lime). For this reason it is recommended
that a regular schedule for deliming be maintained.
The time between cleaning will vary from weeks to months depending
upon water conditions and usage.
The depth of lime buildup should be measured periodically. Heaters
equipped with cleanouts will have about 2" of lime buildup when
the level of lime has reached the bottom of the cleanout opening. A
schedule for deliming should then be set up,based on the amount
of time it would take for a 1" buildup of lime. It is recommended that
the water heater initially be inspected after 6 months.
Example 1:
Initial inspection after 6 months shows 1/2" of lime accumulation.
Therefore, the heater should be delimed once a year.
Example 2:
Initial inspection after 6 months shows 2" of lime accumulation.
Therefore, the heater should be delimed every 3 months.
FIGURE 22.

DELIMING SOLVENTS

UN•LIME is recommended 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 water
heater manufacturer. 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:
1. Drain heater.
2. Remove outer cover plate from lower side of heater jacket.
3. Remove six (6) hex head screws securing tank cleanout plate
and remove plate.
4. Remove lime, scale, or sediment using care not to damage the
glass lining.
5. Inspect cleanout plate gasket, if new gasket is required, see
replacement parts list for item number.
6. Install cleanout plate. Be sure to draw plate up tight by tightening
screws securely.
7. Replace outer jacket cover plate.
9. 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 the
100 models. UN•LIME with the necessary hoses and fittings to
delime your heater is also available as a kit: Up-N-Down Transfer
Kit. Contact your local A.O. Smith dealer, distributor or, A.O. Smith
Corporation, Telephone: (800) 433-2545, Fax: (800) 433-2515 or
Website: www.hotwater.com.
PREPARE THE WATER HEATER
To delime the water heater using the Flo-Jug method, first prepare
the heater for deliming as described in the "Why? When? and How?"
booklet, Form No. 4800. Then install the long plastic male adapter
fitting into the drain valve opening of the water heater. Use teflon
tape and hand tighten only. Do not overtighten.
PREPARE THE UP-N-DOWN TRANSFER KIT
The next step is the preparation on the Up-N-Down Transfer Kit, if
you have not already done so:
1. With the 5 gallon Up-N-Down container in the vertical position, unscrew
the plastic vent cap in the handle and pierce the plastic membrane
over the vent boss under the cap to allow the container to vent.
Note: If your container does not have the vent cap and vent
boss, drill a 3/16" (4.76mm) hole in the handle. When you have
finished deliming you will be able to plug this drilled vent with the
stainless steel screw that is supplied with the kit.
2. Remove the container's cap and cut plastic membrane located in
the 3/4" IPT opening in cap. Take care to not damage the threads.
3. Find the 3/4" male adapter, apply teflon tape to the threaded end
and screw it into the 3/4" IPT opening in the cap.
23
FIGURE 23.