10
Heater Target Temperature (BOIL
TARGET)
The heater target temperature is determined from the
mode of operation and type of demand applied. The
Controller displays the temperature that it is currently
trying to maintain at the operating sensor as BOIL
TARGET in the view menu.
The operating sensor for modes 2, 3, 5 and 7 is the
system sensor. If the Controller is not presently
enabled for heat, it displays “- - -“ in the LCD. In Mode
8, no heater target temperature is generated.
System Pump Operation
The pump contacts operate when:
• A CFH is present based on the tank sensor for
dedicated DHW operation (Mode 3).
• While the heater is firing and Primary/Secondary
piping (Mode 2, 5, or 7) is used. Primary/
Secondary piping reduces standby losses by iso-
lating the heater from the system while the heater
is off.
• During external direct drive operation (Mode 8),
the pump contact closes whenever there is an
internal CFH.
• After the system shuts off the pump remains on for
a few minutes to purge heat from the heater to the
system.
System Pump Purge (DLY)
The controller operates the system pump based on the
Pump DLY setting. Once the system shuts down, the
controller keeps the system pump running for the time
selected.
When Pump DLY is set to OFF, there is no purging.
When Pump DLY is set to ON, the system pump runs
continuously. When on is selected and the control is
configured for outdoor reset, the system pump contin-
ues to run even during Warm Weather Shut Down
(Mode 5).
Heater Minimum (BOIL MIN)
The BOIL MIN is the lowest water temperature that the
Controller is allowed to use as a heater target temper-
ature (e.g. 120 ºF). During mild conditions, if the
Controller calculates a heater target temperature that
is below the BOIL MIN setting, the heater target tem-
perature is adjusted to at least the BOIL MIN setting.
During this condition, if the heater is operating, the
MIN segment turns on in the LCD while the heater tar-
get temperature or heater operating sensor
temperature is viewed.
Additional plumbing and/or controls may be required to
maintain the heater at or above its minimum inlet tem-
perature.
Heater Maximum (BOIL MAX)
The BOIL MAX is the highest water temperature that
the Controller is allowed to use as a heater target tem-
perature. If the Controller does target BOIL MAX, and
the heater outlet sensor is near the BOIL MAX temper-
ature, the MAX segment turns on in the LCD while the
heater target, heater inlet, heater outlet or heater sup-
ply temperature is viewed.
Fig. 18: Warm Weather Shutdown
NOTE:
If the installed heater is designed to operate
at a target temperature less than 80°F, set the BOIL
MIN adjustments to OFF.
