Digital Tank Thermostat - A.O. Smith AWH-35 Instruction Manual

DIGITAL TANK THERMOSTAT

DISPLAY
FACTORY SUPPLIED DIGITAL TANK THERMOSTAT - MODEL MT511Ri
OPERATION
When the water temperature in the storage tank as sensed by
the Digital Tank Thermostat's temperature sensor reaches the
Tank Temperature Set Point the thermostat will end the heating
cycle and HPWH unit will shut down.
A heating cycle will be activated again when the water
temperature sensed at the temperature sensor in the storage
tank drops below the Tank Temperature Set Point minus the
Differential Set Point.
See Figure 11 above as a reference for the instructions that
follow.
Notes: The Tank Temperature Set Point must never be set higher
than 140°F (60°C). This is the maximum temperature the HPWH
can heat the water in the storage tank to. See Maximum System
Temperature on page 10.
The factory Differential Set Point is 3°F (1.7°C). This is the
recommended setting. The Differential Set Point should never be
set lower than the factory setting to ensure the HPWH unit does
not short cycle. This Differential Set Point should not be set any
higher than 5°F (2.8°C).
TANK TEMPERATURE SETTING
1. Press and hold the SET button for 1 second until [ t ] appears
on the LED display then release the button.
2. Use the UP and DOWN buttons to adjust to the desired tank
temperature set point.
3. When complete press the SET button to save the change.
DIFFERENTIAL SETTING
1. Press and hold the UP and DOWN buttons simultaneously
for 5 seconds until [ dIF ] appears on the LED display then
release the buttons.
2. Use the UP and DOWN buttons to adjust to the desired
differential set point.
3. When complete press the SET button to save the change.
4. The operating mode of the thermostat will be shown on the
LED display next as:
[ CoL ] for Refrigeration/Cooling mode or
[ Hot ] for Heating mode.
LED
OUTPUT
UP
BUTTON
SET
DOWN
BUTTON
Figure 11
Note: the factory for operating mode is [ Hot ] and should not
be changed.
TEMPERATURE UNITS SETTING (°F/°C)
To define the temperature units that thermostat will display:
1. Press and hold the UP and DOWN buttons simultaneously
for 30 seconds until [ Uni } appears on the LED display then
release the buttons.
2. Use the UP and DOWN buttons to select [ °F ] or [ °C ].
3. When complete press the SET button to save the change.
4. [ FAC ] will appear on the LED display after saving the
change and the display will then return to normal operation
and display the tank temperature.
Note: Each time the temperature unit display setting is
changed all set points must be re-configured
DISPLAYING MIN/MAX TANK TEMPERATURES
The digital thermostat stores the minimum and maximum tank
temperature readings in memory. To display this data:
1. Press the UP button.
2. The recorded minimum temperature will be displayed
followed by the recorded maximum temperature.
3. Note: to reset the recorded values press and hold the UP
button while the minimum and maximum values are being
displayed.
4. [ rSt ] will appear confirming that the recorded minimum and
maximum temperatures have been cleared.
DISPLAY SIGNALS
During normal operation the LED display will show the actual
measured tank temperature from the tank temperature sensor.
The LED light located above the temperature display (Output)
indicates that the heat pump, the thermostat output, is on.
If the temperature sensor is detached or the temperature is out
of the specified range [ Err ] will be displayed on the LED display.
24
SET
BUTTON