Safety Controls; Water Temperature; Safety Precautions - Rheem Light Duty Commercial Electric Water Heater Use And Care Manual

A. Do turn off power to water heater if it has been subjected to over
heating, fire, flood or physical damage.
B. Do Not turn on water heater unless it is filled with water.
C. Do Not turn on water heater if cold water supply shut-off valve is
closed.
D. If there is any difficulty in understanding or following the OPERATION
or MAINTENANCE instructions, it is recommended that a qualified
person or serviceman perform the work.
1. WATER TEMPERATURE SETTING — The temperature of the water in
the water heater can be regulated by setting the temperature dial of the
adjustable surface mounted thermostats located behind the jacket
access panels. To comply with safety regulations the thermostats are
factory set at 120°F (49°C) or less where local codes require.
Reset Button
Thermostat Protective
Cover
CAUTION!! — Hotter water increases the risk of SCALDING!
This illustration shows the temperature adjustment dial used for setting the
water temperature. Refer to Section 1 - Water Temperature Setting, above, for
more details and safety instructions regarding water temperature setting.
Figure 4. — Thermostat and Protective Cover.
Safety and energy conservation are factors to be considered when
selecting the water temperature setting of the water heater's thermostats.
The lower the temperature setting the greater the savings in energy and
operating costs.
!
DANGER
Hotter water increases the potential for Hot Water SCALDS.
NOTICE: When this water heater is supplying general purpose hot
water requirements for use by individuals, a thermostatically
controlled mixing valve for reducing point of use water
temperature is recommended to reduce the risk of scald injury.
Contact a licensed plumber or the local plumbing authority for
further information.
Operation

SAFETY PRECAUTIONS

Thermostat Dial
Pointer
170 110
120
160
150 140 130
TURN OFF
POWER
BEFORE
SERVICING
!
CAUTION
Hydrogen gas can be produced in a hot water system served by
this water heater that has not been used for a long period of time
(generally two weeks or more). HYDROGEN GAS IS EXTREMELY
FLAMMABLE!! To dissipate such gas and to reduce risk of injury,
it is recommended that the hot water faucet be opened for several
minutes at the kitchen sink before using any electrical appliance
connected to the hot water system. If hydrogen is present, there
will probably be an unusual sound such as air escaping through
the pipe as the water begins to flow. Do not smoke or use an
open flame near the faucet at the time it is open.
TIME / TEMPERATURE RELATIONSHIPS IN SCALDS
Temperature
20°F (49°C)
°C)
125°F (52
130°F (54°C)
135°F (57°C)
140°F (60°C)
145°F (63°C)
150°F (66°C)
155°F (68°C)
!
DANGER
Make certain power to water heater is OFF before removing jacket
access panel(s) FOR ANY REASON.
If adjustment is necessary, turn off power to water heater, remove
jacket access panel and insulation exposing thermostats. The thermostat
protective covers should not be removed . Set thermostat dial pointers,
with a small screwdriver, to desired temperature. (Refer to Fig. 4.)
Replace insulation and jacket access panel. Turn on power to water
heater.
2. SAFETY CONTROLS — The water heater is equipped with a
combination Thermostat and Temperature Limiting Control (ECO) that is
located above the heating element in contact with the tank surface. Non
simultaneous operating heaters have an ECO above the upper element,
and simultaneous operating heaters have an ECO above both upper and
lower elements. Refer to the wiring diagram marked on the back of this
manual to determine which control operating scheme this heater is wired
for. If for any reason the water temperature becomes excessively high,
the Temperature Limiting Control (ECO) breaks the power circuit to the
heating element. Once the control opens, it must be reset manually.
!
CAUTION
The cause of the High Temperature Condition must be investigated
by qualified service personnel and corrective action taken before
placing the water heater in service again.
To reset the Temperature Limiting Control, turn off power to water
heater, remove jacket access panel and insulation. The thermostat
protective cover SHOULD NOT be removed . (Refer to Fig. 4.) Press
red "RESET" button. Replace insulation and jacket access panel before
turning on power to water heater.
7
Time to Produce Serious Burn
More than 5 minutes
1 / to 2 minutes
1
2
About 30 seconds
About 10 seconds
Less than 5 seconds
Less than 3 seconds
1
About 1 / seconds
2
About 1 second
Table courtesy of Shriners Burn Institute