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DRAINING
The heater must be drained if it is to be shut down and exposed
to freezing temperatures. Maintenance and service procedures
may also require draining the heater.
1. Turn off the heater electrical disconnect switch.
2. Close the cold water inlet valve to heater.
3. Open a nearby hot water faucet to vent the system.
4. Open the heater drain valve.
5. If the heater is being drained for an extended shutdown, it is
suggested the drain valve be left open this period.
• Follow FILLING instructions when restoring hot water service.
SEDIMENT 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.
For convenience, sediment removal and lime scale removal should
be performed at the same time.
LIME SCALE REMOVAL
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, heaters and on cooking utensils.
Lime accumulation not only reduces the life of the equipment
but also reduces efciency 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 depth of lime build-up should be measured periodically.
Heaters will have about 3” (76 mm) of lime build-up when the level
of lime has reached the bottom of the cleanout opening or about
1” of lime build-up 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” (25.4 mm) build-up of lime.
Example 1 – Initial inspection shows 1/2” (12.7 mm) of lime
accumulation. Therefore, the heater can be
delimed once a year.
Example 2 – Initial inspection shows 2” (50.8 mm) of lime
accumulation. Therefore, the heater should be
delimed every 3 months.
Sediment and lime scale removal may be accomplished through
the cleanout opening furnished on the heater, see FEATURES.
The heater must be drained. See DRAINING, before removing
cleanout cover on tank.
To dissolve and remove the more stubborn mineral deposits, State
UN•LIME
®
Professional delimer should be used.
State UN•LIME
®
Delimer is an easy to handle patented food grade
acid formulated specically for lime scale removal from all types
of water using equipment. Available in 1 gallon (part no. 4763)
and 5 gallon (part no. 4813) sizes. Hydrochloric base acids are
not recommended for use on glass-lined tanks.
State Form No. 4800 entitled “Why, When and How”, describes
tank cleaning methods and materials. UN•LIME
®
and the booklet
may be obtained through your State dealer or distributor.
The cleanout opening is shown in Figure 9.
To clean heater through cleanout opening, proceed as follows:
1. Turn off water inlet valve, the heater electrical disconnect switch
and open drain valve.
2. Remove outer cover plate from lower side of heater jacket.
3. Remove cover from cleanout opening.
4. Remove lime, scale or sediment using care not to damage the
glass lining.
5. Inspect cleanout plate gasket; if new gasket is required, replace
with State part no. 99038.
6. Install cleanout plate. Be sure to draw plate up tight by
tightening screws securely.
7. Close drain valve, open water inlet line and turn on the burner
electrical disconnect switch.
8. Check for water leakage.
9. Replace outer jacket cover plate.
RELIEF VALVE
At least twice a year, the temperature and pressure relief valve
should be checked to ensure that it is in operating condition. To
check the relief valve, lift the lever at the end of the valve several
times. The valve should seat properly and operate freely.
CAUTION
BEFORE MANUALLY OPERATING A RELIEF VALVE, MAKE
SURE THAT A DRAIN LINE HAS BEEN ATTACHED TO THE
VALVE TO DIRECT THE DISCHARGE TO AN OPEN DRAIN.
FAILURE TO TAKE THIS PRECAUTION COULD MEAN
CONTACT WITH EXTREMELY HOT WATER, PASSING OUT OF
THE VALVE, DURING THIS CHECKING OPERATION.
If the temperature and pressure relief valve on the heater
discharges periodically or continuously, it may be due to thermal
expansion of water in a closed water supply system, or, it may be
due to faulty relief valve.
Thermal expansion is the normal response of water when it is
heated. In a closed system, thermal expansion will cause the
system pressure to build until the relief valve actuation pressure
is equaled. Then, the relief valve will open, allowing some water
to escape, slightly lowering the pressure.
Contact your water supplier or local plumbing inspector on how
to control this situation.
Two common corrections are listed in the CHECKLIST AND
SERVICE INFORMATION that appears later in this manual.