38
TEMPERATURE REGULATION
TEMPERATURE REGULATION
Install Thermostatic Mixing Valves to regulate the temperature of
the water supplied to each point-of-use (for example, kitchen sink,
bathroom sink, bath, shower). Install and adjust the mixing valve
according to its manufacturer’s instructions. See
Figure 35
(page
29).
It is recommended that lower water temperatures be used to avoid
the risk of scalding. It is further recommended, in all cases, that the
water temperature be set for the lowest temperature which satisfies
your hot-water needs. This will also provide the most energy efficient
operation of the water heater.
Short repeated heating cycles caused by small hot-water uses can
cause a temperature increase of the hot water by 30F° higher than
the heater’s temperature settings. If you experience this type of use
you should consider using lower temperature settings to reduce
scald hazards.
WARNING! Even if the water heater’s control system is set
to a relatively low temperature, hot water can scald. Install
Thermostatic Mixing Valves at each point-of-use to reduce the
risk of scalding.
See
Figure 35
(page 29).
Should overheating occur or the gas supply fails to shut off, turn
off the main manual gas shut off valve to the appliance. See
Figure
1
(page 8).
TEMPERATURE CONTROL
Water temperature over
125°F can cause severe
burns instantly resulting in
severe injury or death.
Children, the elderly and the
disabled and are at highest
risk of scald injury.
Feel water before bathing or
showering.
Temperature limiting devices
such as mixing must be
installed when required by
codes and to ensure safe
temperatures at fixtures.
Read instruction manual for
safe temperature setting.
BURN
HOT
HOT
DANGER
HOT WATER CAN SCALD
Water heaters are intended to produce hot water. Water heated to
a temperature which will satisfy space heating, clothes washing,
dish washing, cleaning and other sanitizing needs can scald and
permanently injure you upon contact. Some people are more likely
to be permanently injured by hot water than others. These include
the elderly, children, the infirm, or physically/mentally handicapped.
If anyone using hot water fits into one of these groups or if there is
a local code or state law requiring certain temperature water at the
hot-water tap, then you must take special precautions. In addition
to using lowest possible temperature setting that satisfies demand
of application, to reduce the risk of scalding, install Thermostatic
Mixing Valves (temperature limiting valves) at each point-of-use.
See
Figure 35
(page 29).These valves automatically mix hot and
cold water to limit the temperature at the tap. Before changing the
factory setting on the control system, see
Table 20
.
This water heater is equipped with a control system. See
Control
System Operation
(page 40). Hot water temperatures required
for automatic dishwasher and laundry use can cause scald burns
resulting in serious personal injury and/or death. The temperature
at which injury occurs varies with the person’s age and time of the
exposure. The slower response time of children, aged or disabled
persons increases the hazards to them. Never allow small children
to use a hot-water tap, or to draw their own bath water. Never leave
a child or disabled person unattended in a bathtub or shower.
Setting the water heater temperature at 120 °F will reduce the risk
of scalds.
WARNING! Higher temperatures increase the risk of scalding,
but even at 120°F, hot water can scald. (See
Table 20
). Install
Thermostatic Mixing Valve(s) at each point-of-use to reduce
the risk of scalding.
See
Figure 35
(page 29).
Table 20. Burn Time at Various Temperatures
Water Temperature
°F (°C)
Time for 1st Degree
Burn
(Less Severe Burns)
Time for Permanent Burns
2nd & 3rd Degree
(Most Severe Burns)
110 (43)
(normal shower temp.)
116 (47)
(pain threshold)
116 (47)
35 minutes
45 minutes
122 (50)
1 minute
5 minutes
131 (55)
5 seconds
25 seconds
140 (60)
2 seconds
5 seconds
149 (65)
1 second
2 seconds
154 (68)
instantaneous
1 second
(U.S. Government Memorandum, C.P.S.C., Peter L. Armstrong, Sept. 15, 1978)
Check water temperature at several points of use in your home (for
example, bathtub faucet, shower, or lavatory sink) and adjust the
Thermostatic Mixing Valves as needed. See
Figure 35
(page 29).
The water heater should be located in an area where the general
public does not have access to set temperatures.
Setting the water temperature setpoint at 120°F will reduce the risk of
scalds. Some states require settings at specific lower temperatures.
Check with the code authority having jurisdiction.
The water heaters covered in this manual are equipped with an
electronic control system to regulate water temperature inside the
storage tank. The control system senses temperature from a factory
installed temperature probe installed on the side of the storage tank.
See
Figure 1
(page 8)
and
Figure 2
(page 8).
The water temperature setpoint is adjusted to regulate water
temperature inside the tank. This is an adjustable user setting in the
control system’s “Temperature Menu.” This and all control system
menus are accessed through the UIM (user interface module) located
on the front of the water heater. See
Figure 42
(page 40).
The water temperature setpoint is adjustable from 90°F (32°C) to
160°F (71°C). The factory setting is 120°F (49°C). See
Temperature
Setpoint
(page 40)
for instructions on how to adjust the setpoint
and other settings.
Set the water temperature setpoint at the lowest setting which
produces acceptable hot water supply. This will always provide the
most efficient operation.
