18
TEMPERATURE REGULATIONTEMPERATURE REGULATION
LIMITING THE RISK OF SCALDING
For a variety of reasons, water heaters can produce water that is
much hotter than its temperature setting. Take precautions to prevent
this higher temperature water from reaching the water xtures.
Burn Hazard
To reduce the risk of unusually hot
water reaching the fixtures in the
house, install thermostatic mixing
valves at each point of use.
A properly adjusted thermostatic mixing valve at each point of use
allows you to set the tank temperature to a higher setting without
increasing risk of scalds. A higher temperature setting allows the
tank to provide much more hot water and can help provide proper
water temperatures for appliances such as dishwashers and washing
machines.
Table 5. 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)
HIGH TEMPERATURE LIMIT CONTROLS (ECO)
Both the ELECTRONIC CONTROL and SURFACE MOUNT
CONTROL model water heaters are equipped with one or more
ECO (energy cut o) non adjustable high temperature limit control(s).
An ECO is a normally closed switch that opens (activates) on a
rise in temperature. If the ECO switch contacts open (activate)
due to abnormally high water temperatures, the ECO will lock-out
and disable further heating element operation. When the water
temperature falls to safe levels the ECO(s) can be reset as described
in the next two sections:
Burn Hazard
Controls may become hot during normal
operation. Care should be taken to
prevent burns.
SURFACE MOUNT CONTROL MODELS
Surface Mount Control models have multiple surface mounted
Thermostat/ECO combination controls. One for each installed
heating element. See the Surface Mount Control wiring diagrams,
Figure 19 (page 42), Figure 20 (page 43), and Figure 24 (page
47). The ECO high temperature limit switch contacts on each
control will open when the tank temperature reaches approximately
200°F/93°C. If activated, the ECO reset button will be slightly
extended and sti to the touch. When the ECO switch contacts open
(activate) voltage to ONE heating element ONLY is terminated to
prevent further heating operation of that element. Voltage may still
be present at other heating elements and they may still be heating
the water.
The ECO is a manual reset switch. Should one or more ECO switches
activate, the tank temperature must drop below 120°F/49°C before
an ECO can be reset. To manually reset an ECO:
1. Disconnect the power supply to the water heater.
2. Allow the tank temperature to cool below 120°F/49°C.
3. Remove the front control cover from the eected control(s).
4. Press the manual reset button on each of the eected controls.
5. Once the control(s) has been reset the control cover should be
replaced prior to restoring power to the water heater.
ELECTRONIC CONTROL MODELS
The ECO high temperature limit switch is located inside the
immersion Temperature Probe (two red wires) on ELECTRONIC
CONTROL models. The ECO switch contacts will open when the
water temperature reaches approximately 202°F/94°C. When the
ECO switch contacts open (activate) the electronic control system
locks out and displays a Fault message. Voltage to the contactor
coils and heating elements is terminated to prevent further heating
operation.
Should the ECO activate, the water temperature must drop below
140°F/60°C before the control system can be reset. Once the water
temperature has cooled below this point the power supply to the
water heater must be turned o and on again to reset the control
system.
THERMOSTAT CONTROLS
The water heaters covered in this instruction manual are equipped
with adjustable thermostat controls to control water temperature. 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
persons age and duration of exposure. The slower response time
of children, the elderly or disabled persons increases the hazards to
them. Never allow small children to use a hot water tap or draw their
own bath water. Never leave a child or disabled person unattended
in a bathtub or shower.
The water heater should be located in an area where the general
public does not have access to set temperatures. Setting water
heater temperatures at 120°F (49°C) will reduce risk of scalds. Some
areas require settings at specic lower temperatures.
Printed on 5/6/2022 7:17 AM CT
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