Temperatures Menu - A.O. Smith dre-52 Service Handbook

TEMPERATURES MENU

Operating Set Point
User adjustable setting 90°F to 190°F range;
factory default is 120°F. When the water
temperature sensed by the control system
from the immersion Temperature Probe
reaches the Operating Set Point the control
system will end the heating cycle. A call for
heat will be activated again when the water
temperature drops below the Operating Set
Point minus the 1st Differential Setting.
Example: Operating Set Point is 120°F, the 1st Differential Setting is 2°F (factory default). A
call for heat will be activated when the sensed water temperature drops to 118°F.
Differential Settings
Adjustable user setting(s) 1°F to 20° range; factory default is 2°F. The water heaters covered
in this manual will have 3, 6 or 9 heating elements. Each group of 3 heating elements is one
"Bank" of heating elements. Heating elements are energized in Banks of 3. Each Bank of
heating elements will have a Differential Setting associated with it. Differential Settings are
located in the Temperatures Menu.
There is a 1st Differential Setting on all models. There will be one additional Differential
Setting visible/adjustable for each additional Bank of (3) heating elements.
Operating Sequence: With an Operating Set Point of 120°F and all Differential settings at
2°F the On/Off sequencing of heating element Banks would be as follows:
BANK NUMBER
Bank 1
Bank 2
Bank 3
Tank Temperature
Non adjustable information display. Current water temperature as sensed by the control
system from the immersion Temperature Probe.
Tank Probe Offset
User adjustable setting -5°F to +5°F range; factory default is 0°F. If the current Tank
Temperature is sensed (from the immersion Temperature Probe) at 120°F and the offset is
adjusted to -5°F the control system would calibrate or "offset" the Tank Temperature to
115°F. Heating cycles would then start/stop based on the calibrated Tank Temperature.
Used to calibrate for slight differences in control system temperature sensing. This can
improve the precision of temperature control in the storage tank and at points of use. This
feature can also be used to compensate for building recirculation loops (hot water returning
to the storage tank) that may cause the heating cycle to terminate prematurely.
Servicing should only be performed by a Qualified Service Agent
ELECTRONIC CONTROL SYSTEM
DIFFERENTIAL SETTING
2°F
2°F
2°F
TURN ON TEMP
118°F
116°F
114°F
52
TURN OFF TEMP
120°F
118°F
116°F