Tag Archives: Snowmelt controls

General Tips for Using the ETO2 Controller for Snow Melting Systems


This article is intended as a  general guide to help users of snowmelt systems that utilize the ETO2 and ground sensor. For more detailed information, please refer to the Owner’s and Installation Manual.

The ETO2 is an electronic controller for fully automatic, economical ice and snow melting for outdoor areas. The controller is used for snow melting and roof deicing systems utilizing in-ground sensors.

The ETOG in-ground sensor detects both temperature and moisture and signals the controller when conditions warrant. The ETO2 unit then sends power to the cable, activating the snowmelt system and warming the driveway surface.

The ETO2 features an easily operated encoder button and backlit graphic display to ensure quick and easy configuration and simple indication of temperature, status, etc.

Controller for an automated snow melting system
The ETO2 controller used for snow melting systems that utilize an in-ground snow sensor.

The control unit is suitable for controlling electric heating cables in a 1 or 2 zone system. It also features advanced two-stage output control for economic operation.

This article only covers some general startup and troubleshooting information for current owners. For installation instructions, please refer to the installation manual provided. (Available on our snowmelt product documentation web page.)


Turn the encoder knob on the front of the ETO2 to scroll through the available options.

Push the Encoder knob to “enter” your selection.

When the ETO2 is switched on for the first time, Celsius” or “Fahrenheit” must be selected. Turn the encoder knob until the required temperature scale is highlighted. Then OK the selection by depressing the encoder knob.

SENSOR 1 is shown on the display, allowing the type of sensor connected for input 1 to be selected. (ETOG ground sensor or ETOR gutter sensor and outdoor sensor.) OK the selection by depressing the encoder knob.

SENSOR 2 is then shown on the display, allowing the type of sensor connected for input 2 to be selected. If no sensor is connected for input 2, OFF must be selected.

OUTDOOR SENSOR: Select if outdoor sensor ETF is connected to terminals 31, 32. If no sensor ETF is connected, OFF must be selected. Press encoder knob for OK.

To select the application type, turn the encoder knob and then depress it.




Select the appropriate option and press OK. The system is now set up, and will begin operating fully automatically, in accordance with the pre-configured standard program, see FACTORY SETTINGS. Alternative settings can also be made, see SETTINGS.

Status and afterheat data for zones 1 and 2 are now shown on the display.


The ETO2 is equipped with an easily operated encoder knob/button (turn and press) and a display which describes the current situation. The display is backlit and illuminated by pressing the encoder knob. The illumination is automatically switched off after 30 seconds.

Press the encoder knob and the Main Menu will be displayed. Turn the knob to scroll through the options. Not all the options are shown on the display at once, but they can be accessed by turning the encoder knob. Press OK to select a highlighted option.


Please note that incorrect sensor setup may lead to poor or lacking ice and snow melting. Press OK and a submenu will be shown on the display. Select the parameter to be set and press OK.


FORCE HEAT – OFF Manual start of forced heat. Press OK and select ON to start Forced heat. ETO2 controller will heat in the pre-programmed AFTERRUN time, see AFTERRUN 1 and 2.

SELECT SCALE    C – Whether temperature is to be displayed in Celsius (C) or Fahrenheit (F) can be selected here. Select the required scale and press OK. Press OK to return to the SETUP menu.


When changing the settings or require a new process start, the ETO2 can be restarted in this menu.


Restart operation. Keeping your current settings. The ETO2 will go to the initial status display. If it is necessary to calibrate the temperature measured by the ETOG sensor, please follow the steps below:

  1. Disconnect the sensor from terminals 11 and 12 (sensor heating) of the ETO2.
  2. Wait a few hours until the sensor has acquired the same temperature as the ground.
  3. Measure the real ground/sensor temperature and compare it with the temperature shown on the ETO2 display.
  4. Program the offset for the sensor concerned to match the difference between the two temperatures (displayed/real). Adjust the necessary offset using the encoder button. Press OK.
  5. Reconnect the sensor to terminals 11 and 12 of the ETO2.

NOTE: With ETOG-55 sensor, the temperature shown on the ETO2 display is always the core temperature of the sensor.


By errors in the snow melting system, it is recommendable to check the setup of the ETO2. Activate the menu by pressing the adjustment knob, press SHOW INFO and readout the programmed application. By errors in the setup, activate REINSTALL with factory code 1202.

Check that all connections are placed correctly, and that cables are fastened in the clamps. For more information, contact our technical support department 801.948.7545.

Display shows HEAT ON in zone 1 / 2 but the snow is not melting: Wait 1-2 hours.

Check under the snow, if the snow is beginning to melt the system is OK.

Check the heating cables for defects or bad connections.

It is too cold for snow melting (power/m2) or undersized heating cables/ hydronic heating system.

Display does not show HEAT ON in zone 1 / 2 The temperature is higher than SET TEMP. Adjust SET TEMP to higher temperature.

The snow around the ground sensor is melting/drifting snow has exposed the sensor.

AFTERRUN time must be increased. Alternatively, FORCED HEAT can be activated.

Igloo effect around the sensor. The ground sensor has melted an insulated hollow under the snow. Activate FORCED HEAT or, alternatively, set MOIST SENSOR to OFF.

The temperature is lower than the OFF TEMP setting.

Depending on dimensioning, the system has a lower temperature limit, at which the system can melt the snow. Try melting the snow with FORCE HEAT, before OFF TEMP is changed.

The heat does not shut off after ice/snow melting: AFTERRUN time is too long – reduce AFTERRUN time and activate RESTART in the menu.

Moisture detection in the ETOG/ETOR sensor is turned off – set MOIST CTRL to ON in the menu.

If the ALARM button flashes red, one of the following errors has occurred. This can be displayed under the menu: ALARM.
RETURN TEMP LOW Water temperature on return pipe is too low.
SUPPLY TEMP HIGH Water temperature on supply pipe is too high.
RETURN SENSOR Return sensor defective.
SUPPLY SENSOR Supply sensor defective.
TEMP SENSOR 1 Temperature sensor in ground or roof sensor 1 defective.
TEMP SENSOR 2 Temperature sensor in ground or roof sensor 1 defective.
OUTDOOR SENSOR Outdoor sensor defective.
SENSOR HEATER Short circuit of heating element in ground or roof sensor.
FROST PROTECT Active frost protection due to low return temperature (water based systems only)

Preparing for Winter’s “Perfect Storm”

Getting the Most out of Your Snowmelt System During Extreme Snow Events

Your Warmzone snow melting system was designed according to ASHRAE standards, meaning it was designed specifically for typical winter conditions in your area – and then some. But every now and then Mother Nature unleashes a furious “perfect storm” of epic proportions that overwhelm even the most hardy winter-weather cities. Snow plows, public transportation and basic city services can be brought to their knees because of unusually low temperatures and record breaking snowfall. Even fully automated radiant snow melting systems are faced with some unique challenges posed by the extreme conditions. Fortunately, Warmzone snowmelt systems include features that allow you to better cope with winter anomalies such as an extreme snow event.

Tips – Preparing for an Extreme Snow Event

If you’re faced with a potential storm of record magnitude, follow the steps outlined below.

Timer: If you purchased a timer with your heated driveway system, use this manual override feature to pre-heat your driveway 2-4 hours before the storm hits. (Once the snow starts to fall, the snow switch will detect precipitation and automatically activate the system.)

Aerial Mount Snow Switch: If you don’t have a timer, you can still manually activate the system using the WS-AUX controller or the aerial-mount snow switch. To activate the system using the snow switch, flip the toggle switch on the side of the unit up so that it is in the ON position. This activates the system and begins pre-heating the driveway. (NOTE: Remember that the system will remain on until you return the toggle switch to AUTOMATIC or STANDBY.)

Control display panel for automated snow melting system

WS-AUX Controller: Activating the system using the WS-AUX controller is the most convenient method for pre-heating your driveway or walks. Turning the sensor override switch on the WS-AUX to the MANUAL ON position will activate the snowmelt system continuously. Pressing the MANUAL ON button on the WS-AUX will not trigger the sensor to run continuously but will initiate one “drying cycle.” This mode can be used to test the system or clear any remaining un-melted snow. This function allows the user to run a cycle without having to remember to turn the system back off. The sensor will initiate one drying cycle and revert to automatic mode, thereby making it ready for detection of the next storm. The MANUAL ON mode can be activated directly from either AUTOMATIC or STANDBY mode. The user may reset and clear the drying cycle by pressing STANDBY.

The WS-AUX will show the current setting of the manual override switch for the attached snow sensor. The sensor’s override switch will always take precedence over the WS-AUX setting. If, for example, the WS-AUX has placed the sensor into STANDBY mode and the sensor switch is moved to MANUAL ON, the WS-AUX will show a change to MANUAL ON mode. Whenever the sensor’s switch overrides the WS-AUX’s setting, then returns to AUTOMATIC mode, the WS-AUX will also revert to AUTOMATIC mode.

In-Ground Snow Switch: For those utilizing the pavement-mount snow switch, refer to page 6 and 9 of the ETO2 User’s Guide Programming Manual.

Working with the Controller

Pre-heat Your Driveways in Preparation for Record Snowfalls

Main menu of the snow melting system controller

In MAIN MENU of the controller, turn the dial to scroll down to SETUP (as seen on page 6 of the User Manual). After selecting SETUP, scroll down to FORCE HEAT and push the dial in to select. This will then activate the system.

Naturally, you do not want to turn the snow melting system on too late or too early, so follow the local weather reports and make your best guess as to when the storm’s first snow will fall. It is recommended to begin pre-heating your driveway (or sidewalks) 2 to 4 hours before any excessively large storm hits. This gives your system a “head start” that will help it to keep up with the unusually heavy snowfall.

Remember, pre-heating the driveway is not necessary in most other cases. Your automated snow melting system was designed to effectively handle typical winter storms in your area. The steps outlined here are simply offered as suggestions to help you cope with the occasional record-breaking snow storm.

Example of dialogue seen on screen of the snowmelt system controller. The heat will stay on the amount of time the designated in the AFTERRUN mode. Once the FORCE HEAT cycle is complete, the device will default back to AUTOMATIC mode. The falling snow will then keep the system on.

Setting the Afterrun time in the controller menu

Adjusting the AFTERRUNTo adjust the AFTERRUN, remain in the SETUP menu.

Refer to page 10 of the User’s Manual.

Set the time for how long before the snowfall that you want to pre-heat the driveway area. Typical time ranges between 2 and 4 hours, depending on the storm.)

Check out Warmzone’s helpful instructional videos on YouTube:
Video instructions on tuning your pavement mount controller

Video instructions for programming your WS-5C aerial-mount snow sensor

Remember, a snow melting system is only as good as it’s installation. So if you’re considering purchasing a radiant heat system, be sure to deal only with experienced professionals who legitimately offer a dedicated support team that will work with you and guide you through the installation process.

And when those record breaking storms come calling at your doorstep, be sure to get the most out of your ClearZone snow melting system by talking to the pros at Warmzone. If you have any questions, feel free to pick up the phone and call Warmzone for additional radiant heat information or to learn how to best deal with extreme snow events. Our business is built on customer service, and we take great pride in being responsive to our customers needs, so don’t hesitate to contact an experienced radiant heat professional at Warmzone today (888.488.9276).