Installation Manual

41
TABLE 15
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)
The water heaters covered in this manual are equipped with an
electronic control system to regulate the water temperature inside
the storage tank. The control system senses temperature from
two factory installed temperature probes, one installed in the top
of the storage tank and one installed near the bottom, See Figure
3 on page 8 and Figure 4 on page 9 for location.
The “Operating Set Point” is adjusted to regulate water temperature
inside the storage tank. This is an adjustable user setting in the
control system’s “Temperatures 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 52.
The Operating Set Point is adjustable from 90°F (42°C) to 180°F
(82°C). The factory setting is 120°F (49°C). See Operating Set
Point And Differential Adjustment on page 45 for instructions on
how to adjust the Operating Set Point and other user settings.
Set the Operating Set Point at the lowest setting which produces
an acceptable hot water supply. This will always provide the most
energy efcient operation.
MODULATION
The water heaters covered by this manual are capable of modulating
their ring rate. The CCB monitors the water temperature in the tank
and regulates the ring rate to achieve the target temperature setpoint.
The ring rate is dictated by the hot water draw, proximity to the tank
temperature setpoint, and various other temperature limitations.
Periodically, when the heater is in modulation mode, the CCB will increase
the blower speed for a short period of time to clear out any condensation
that has accumulated in the heat exchanger then decreases the blower
speed back to the modulating ring rate required to maintain the desired
tank temperature setpoint. This ramping up and down of the blower
speed is considered normal operation of the water heater.
HIGH TEMPERATURE APPLICATIONS
Higher operating temperatures cause more wear on all water heaters
and will decrease the life span of the water heater. Consider installing
a small booster water heater for high temperature applications, such
as commercial dishwashers, to raise the outlet temperature from the
larger primary water heater to the desired point of use temperature.
Contact your local distributor or call the technical support phone number
listed on the back cover of this manual for further technical assistance.
Tank Temperature 103°F
Operating Set Point 120°F
Status: Heating
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MANUFACTURER / MODEL INFORMATION
Figure 50
HIGH TEMPERATURE LIMIT CONTROL (ECO)
This water heater is equipped with an ECO (energy cut off) non
adjustable high temperature limit switch. The ECO is a normally
closed switch that opens (activates) on a rise in temperature.
The ECO is located inside the Upper Temperature Probe (two red
wires), see Figure 3 on page 8 for location. The ECO switch contacts
will open when the water temperature reaches approximately 202°F
(94°C) and close at approximately 140°F (49°C).
If the ECO activates (contacts open) due to abnormally high water
temperatures in the storage tank the control system will immediately
de-energize the 24 VAC Gas Valve and end the current heating
cycle. The control system will "lock out" disabling further heating
operation. The control system will display the "Energy Cut Out
(ECO)" Fault message on the LCD screen. It is important that a
Qualied Service Agent be contacted to determine the reason for
the ECO activation before resetting the ECO. Once the reason has
been determined and corrected the ECO can be reset as follows:
Should the ECO activate, the water temperature must drop below
140°F (49°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 off and on again to reset the control system.
THERMOSTAT CONTROL
Water temperature over 125°F (52°C)
can cause severe burns instantly
resulting in severe injury or death.
Children, the elderly and the
physically or mentally disabled are at
highest risk for scald injury.
Feel water before bathing or
showering.
Temperature limiting devices such as
mixing valves must be installed
when required by codes and to
ensure safe temperatures at fixtures.
Hot water temperatures required for automatic dishwasher and
laundry use can cause scald burns resulting in serious personal
injury and/or death. Table 15 shows the approximate time-to-
burn relationship for normal adult skin.
The temperature at which injury occurs varies with the person’s
age and duration of exposure. The slower response time of
children, the elderly or disabled persons increases the hazards
to them. If anyone using hot water provided by the water heater
being installed ts into one of these groups or if there is a local
code or state law requiring a certain water temperature at the
point of use, then special precautions must be taken.
In addition to using the lowest possible temperature setting that
satises the demand of the application a mixing valve can be
installed at the water heater (see Figure 8 on page 14) or at the
hot water taps to further reduce system water temperature.
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 the Operating Set Point at 120°F (49°C) will reduce the
risk of scalds. Some States require settings at specic lower
temperatures.
TEMPERATURE REGULATION