EPU‐D Display and Programming 23
059840‐00 Rev. A
Heat‐Timer Corp.
EPU‐D Display and Programming
EPU‐D Control Module Status LEDs
The EPU‐D has three status LEDs:
The following table describes the various status LED combinations.
Display and Variable‐Function Buttons
The EPU‐D display shows the system sensor temperature
(when Sensor Type = Heating System Sensor) or the
outdoor temperature (when Sensor Type = Pressuretrol)
and appropriate operation messages. See “Display Icons
and Messages” on page 24 for more information.
The area above the variable‐function buttons displays the
current function for each button.
LED
Description
Call for Heat
Red LED that indicates the outdoor temperature sensor calls for heat.
Indoor Satisfied
Green LED that indicates the system is in cycle.
Heat Circ Estab
Amber LED that indicates heat circulation has been established.
LED
Description
Red
Amber Green
ON
OFF
OFF
The outdoor temperature sensor calls for heat, but heat established / heating
system sensor temperature has not been reached.
ON
ON
ON
Heat circulation has been established. The Cycle‐ON segment is being timed.
OFF
ON
ON
The Cycle‐OFF segment is being timed. Heat is still established.
OFF
FLASH
OFF
The EPU‐D is in thermal lockout. The control will not call for heat until the
temperature of the return pipe drops to 25°F below the system setpoint setting.
OFF
OFF
ON
The system is in cycle.
OFF
OFF
OFF
Indicates the control season is set to Winter and the outdoor temperature is above
the setting of the outdoor temperature sensor.
