Minimum Water Temperatures (Domestic Hot Water) - A.O. Smith 400 - 2100 Installation & Operation Manual

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Domestic water heaters
Thermostat adjustment procedure
1. Press all three (3) buttons (SELECT, +, -) simultaneously
and hold for three (3) seconds. The Adjust menu will
appear in the controller display.
2. Press and release the SELECT key to step through all
available settings.
3. Setpoint Targets 1 & 2 and DIFFs 1 & 2 need to be set
to the desired settings.
4. To access all settings, the Advanced/User dipswitch
should be set to the "Advanced" position.
5. Once setpoints are adjusted, the dipswitch may be set
back to the User position if desired.
6. After all adjustments have been made, allow 10 seconds
for the controller to revert back to its operating mode.
Note: The unit will not run while the controller is in Adjust
Mode.
Minimum water temperatures (domestic
hot water use)
Domestic water temperatures:
This high efficiency water heater should be operated at a
temperature setting high enough to prevent condensing of
the products of combustion on the unit's heat exchanger or
in the attached venting system. Use extreme caution when
storing water at elevated temperatures. A water temperature
setting maintained above the dew point of the products of
gas combustion should prevent condensate formation and
ensure proper performance of the venting system. The
manufacturer recommends the use of a properly sized
thermostatic mixing valve to supply domestic hot water at
temperatures less than 140°F (60°C). Storing the water at a
higher temperature and thermostatically mixing the water
will increase the available quantity of mixed hot water,
greatly reducing the possibility of condensate formation
on the heat exchanger or in the venting system and help
prevent the growth of water borne bacteria.
Adequate care MUST be taken to
NOTICE
prevent a potential scald injury when
storing water at elevated temperatures
for domestic use.
Inlet water temperatures below the specified minimum
recommendations can excessively cool the products
of combustion resulting in condensation on the heat
exchanger. Condensation on the heat exchanger can cause
operational problems, bad combustion, sooting, flue gas
spillage and reduced service life of the related components.
Installation & Operation Manual
(continued)
An appliance allowed to operate at return
CAUTION
temperatures below the specified minimum
setting may experience problems with
the operating controls, safety switches,
obstruction of the flue gas passages on the
heat exchanger, incomplete combustion,
and possible flue gas spillage. Sustained
operation at lower than specified water
temperatures
conditions that may result in personal
injury or non-warrantable damage to the
appliance.
The maximum temperature setpoint that can be programmed
into the control module from the Operator Interface for water
heater operation is 190°F (88°C). The control is factory pre-set
at approximately 120°F (49°C). Facilities with small children or
invalids may require 120°F (49°C) or a lower temperature setting
to reduce risk of scald injury. Some states may require a lower
temperature setting. Check with your gas supplier for local
requirements governing the temperature setting. Remember,
no water heating system will provide exact temperature at all
times. Allow a few days of operation at this setting to determine
the correct temperature setting consistent with your needs.
1. This water heater, when set at the
NOTICE
lower temperature setting, is not capable of
producing hot water of sufficient temperature
for sanitizing purposes.
2. Higher
increases the ability of the water heater
to supply desired quantities of hot water,
however remember hotter water increases
the risk of scald injury.
Figure 8-5_Danger Warning
may cause hazardous
stored water temperature
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