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Operational Description
The DIGI-LUX is not an on/off control device typical of thermostats used with household heating systems. The DIGI-LUX
is designed to pulse the supply voltage to the STEP Warmfloor™ radiant heat system to help closely match the system
heat output with the heating needs for that zone and to prevent temperature overshoot typical with other heating systems.
This pulsing operation provides you with the maximum level of energy efficiency and highest level of personal comfort
possible.
The pulsing operation of the DIGI-LUX is based upon the users programmed set point and the measured ambient
temperature. If the ambient temperature is below the set point, the DIGI-LUX will pulse the STEP Warmfloor™ system on
to heat up the zone. As the zone temperature begins to approach the programmed set point, the DIGI-LUX will pulse the
system on for shorter time periods. Refer to Figure B for a representation of the pulsing operation of the DIGI-LUX.
Figure B
DIGI-LUX Pulsing Characteristics
The high energy efficiencies achieved with a STEP Warmfloor™ system controlled by a DIGI-LUX is due to the
continuous pulsing operation of the system. This continuous pulsing allows the system to continuously add the right
amount of heat to maintain a constant and comfortable environment. With a traditional forced air on/off controlled heat
system, the system is on and off for long durations requiring significant heat input each time the thermostat calls for heat.
This results in a variable and drafty environment with low energy efficiencies compared to radiant heat.
This pulsing operation of the STEP Warmfloor™ system is designed to prevent overheating of the zone. Also, this pulsing
operation prevents the zones air temperature from reaching the programmed set point. The zones maximum air
temperature will be a few degrees below the programmed set point as is represented above in Figure B. Adjusting the set
point up a few degrees higher than the desired air temperature will compensate for this difference. It is intended that the
maximum zone temperature is a few degrees below the set point to prevent the DIGI-LUX from de-energizing the STEP
Warmfloor™ system for a long time duration, resulting in a significant drop in radiant energy into the zone and a drop in
system efficiency. The DIGI-LUX maximizes the efficiency of the STEP Warmfloor™ system by only requiring the system
to gently replace the heat that is lost from the zone.
Important Note for Floor Warming Systems: The DIGI-LUX is designed for total heating applications and only calls for
the amount of heat necessary to heat the space. Consequently, the floor may not feel noticeably warm to the touch. If a
DIGI-LUX is used to control a floor warming system, it may be necessary to program the DIGI-LUX set point to a
temperature that is at least 3 to 5°F higher than the set point on your primary heat system thermostat to prevent your
primary heat system from de-energizing the floor warming system for long durations.
Installation
The process of installing the DIGI-LUX involves preplanning of mounting locations and roughing in of the necessary
hardware. The installation of the DIGI-LUX typically occurs during new construction or a remodel project where access to
the walls is possible for the rough in work. If access to the walls is not possible, as during some remodel projects, the
DIGI-LUX installation may require the use of surface mounted raceway products such as those manufactured by
Wiremold® (www.wiremold.com).
Plan mounting
locations Thermostat – Locate the thermostat approximately 60” off the floor in a location that is most
representative of the zone that it controls. Do not install where exposed to direct sunlight or
drafts.
Regulator – The regulator is typically located adjacent to the low-voltage transformer(s) that it
controls. The regulator, along with the transformer(s), are air cooled devices and need to be
mounted in a well ventilated area.
Programmed Set point
Measured Air Temperature
Pulse On
Pulse Off
