Automatic Snow and Ice Melting System Control

Features & Benefits

  • Automatic snow/ice melting control
  • Operates electrically- and mechanically held contactors
  • Energy management computer (EMC) interface
  • Accommodates MI, constant wattage and self-limiting heaters
  • Multiple sensor capability
  • Heater hold-on and test capability
  • C-UL-US
  • Simple to install and operate
  • Low energy costs
  • Minimum energy costs
Snow Switch model APS-3C snow and ice melting control

Snow Switch model APS-3C snow melting and deicing control


APS-3C Dimensional Drawing

APS-3C Dimensional Drawing


APS-3C Datasheet C Series Manual Snow and Ice Sensor Datasheet

The APS-3C Snow Switch when used with compatible sensors automatically controls snow/ice melting heaters, ensuring minimum operating costs. Typical applications include pavement, sidewalk, loading dock, roof, gutter and down spout snow/ice melting. The APS-3C is interchangeable with earlier APS–3 models.

The adjustable hold-on timer continues heater operation for up to 10 hours after snow stops to ensure complete melting. The optional RCU–3 Remote Control Unit can be located where system operation can be conveniently observed. It duplicates many of the controls and indicators on the APS-3C front panel. It is used to clear tracked and drifting snow that may not land on a sensor.

The calibrated 40°F to 90°F (4°C to 32°C) high limit thermostat prevents excessive temperatures when using constant wattage and MI heaters. It also permits safe testing at outdoor temperatures too high for continuous heater operation. The temperature sensor is included.

The APS-3C provides a relay closure interface for use with energy management computers (EMC). This feature can also be used for general purpose remote control and annunciation and other advanced applications.

All sensor and communications wiring is NEC Class 2. This simplifies installation while enhancing fire and shock safety. The APS-3C can interface up to six sensors from the CIT–1 product family. More sensors provides superior performance by better matching the controller to site performance requirements.


Area of use Nonhazardous locations
Protection NEMA 3R
Cover attachment Hinged polycarbonate cover, lockable
Entries 3 × 1-1/16″ entries
Material Polycarbonate
Mounting Wall mounted
Supply ETI PN 22470: 120 VAC, 50/60 Hz, 35 VA
ETI PN 22471: 208-240 VAC, 50/60 Hz, 35 VA
Load ETI PN 22470: 120 VAC, 24 amp max. inductive
ETI PN 22471: 240 VAC, 24 amp max. inductive
Contact type Form C
Maximum Ratings Voltage: 240 VAC
Current: 24 amps
Heater hold-on timer 0 to 10 hours; actuated by snow stopping or toggle switch
System test Switch toggles the heater contact on and off. If temperature exceeds high limit, heater cycles to prevent damage.
Snow/Ice Sensors
Sensor type Up to 6 sensor from the CIT–1 product family
Circuit type NEC Class 2
Lead length Up to 500′ (152m) using 18 AWG 3-wire jacketed cable
Up to 2,000′ (609m) using 12 AWG 3-wire jacketed cable
High Limit Thermostat
Adjustment range 40°F to 90°F (4°C to 32°C)
Dead band 1°F (0.6°C)
Sensor type Thermistor network
Circuit type NEC Class 2
Lead length Up to 500′ (152m) using 18 AWG 2-wire jacketed cable
Up to 1,000′ (504m) using 12 AWG 2-wire jacketed cable
Energy Management Computer (EMC) Interface
Inputs OVERRIDE ON (10 ma dry switch contact)
OVERRIDE OFF (10 ma dry switch contact)
Outputs SUPPLY (10 ma dry switch contact)
SNOW (10 ma dry switch contact)
HEAT (10 ma dry switch contact)
HIGH TEMP (10 ma dry switch contact)
ALARM (10 ma dry switch contact)
Operating temperature −40°F to 160°F (−40°C to 71°C)
Storage temperature −50°F to 180°F (−45°C to 82°C)


Order Number Description
22470 APS–3C Control Panel, 120 VAC
22471 APS–3C Control Panel, 208/240 VAC
21357 RCU–3 Remote Control (Optional)
19272 High Temperature Sensor w/ 20′ (6m) lead (Qty 1 included)
22690 PTS–100 Embedded Temperature Sensor (Optional)