Bradford White UCG100H199 Installation & Operation Manual page 37

Sediment and Lime Scale Removal
Waterborne impurities consist of the particles of soil and sand, which settle out and form a layer of sediment on
the bottom of the tank. The amount of calcium carbonate (lime) released from water is in direct proportion to
water temperature and usage. The higher the water temperature or water usage, the more lime deposits are
dropped out of the water. This is the lime scale which forms in pipes, water heaters, and on cooking utensils.
Lime accumulation not only reduces the life of the equipment but also reduces efficiency of the water 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
of deliming be maintained. The depth of the buildup should be measured periodically. Water heaters will have
about 3 in (7.6 cm) of lime buildup when the level of lime has reached the bottom of the cleanout opening or
about 1 in (2.5 cm) of lime buildup if it has reached the drain valve opening. A schedule for deliming should be
set up, based on the amount of time it would take for a 1/2 in (1.3 cm) of lime to build up.
Example: Initial inspection shows a ½ in (1.3 cm) of lime accumulation. Therefore, the water heater should be
delimed once a year.
To Remove Sediment and Lime Scale
1. Drain the heater. Refer to Draining the Water Heater instructions in this section.
2. Remove the outer cover plate from lower side of water heater jacket.
3. Remove the cover and gasket from cleanout opening.
4. Remove the lime, scale, or sediment while using care not to damage the glass-lining.
5. Inspect the cleanout plate gasket. Replace the gasket if necessary (contact local distributor for correct
part number).
6. Install the gasket and cleanout plate. Be sure to draw the plate up tight by tightening screws securely.
7. Close the drain valve. Open a hot water fixture to allow air to escape. Open the cold water supply to
water heater and allow the tank to fill. Follow the lighting instructions.
8. Check for water leakage.
9. Install the outer jacket cover plate.
Anode Inspection and Replacement
This water heater is equipped with multiple sacrificial anodes. Anodes protect the glass-lined tank from
corrosion by sacrificing themselves through electrolysis. When the anode material is consumed, there is no
more protection and corrosion of the tank accelerates.
Inspection of the anode every 6 months allows you to identify the rate of anode degradation. The anode should
be replaced when its diameter is 3/8 in (1 cm), or annually whichever is first. Aggressive, very hot, and/or
softened water causes rapid consumption of the anode requiring frequent inspections. The replacement
anodes rods are available from your plumbing professional.
To Inspect or Replace an Anode
The anodes on this water heater are easily accessible from the top of the water heater making replacement
simple and quick. Use the following procedure to remove and inspect the anodes.
1. Drain the heater. Refer to Draining the Water Heater instructions in this section.
2. Flush the heater. Refer to Flushing the Water Heater instructions in this section.
3. Remove the plastic plug covering the anode.
4. Remove the anode using a socket of the appropriate size. Sometimes a breaker bar will need to be
used. Do NOT use an impact wrench.
5. Inspect and replace the anode as required. Use pipe tape or sealant when reinstalling the anode.
6. Close the drain valve. Open a hot water fixture to allow air to escape. Open the cold water supply to
water heater and allow the tank to fill.
7. Check your anode and drain valve for leaks.
8. Replace the plastic cover that covers the anode.
9. Follow the lighting instructions.
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