APS–3C Snow Switch
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 RCU–3 Remote Control Unit supplied is 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. Using more sensors
provides superior performance by better matching the controller to site performance requirements.
| Specifications | |
| Enclosure Rating | NEMA 3R |
| Enclosure Material | Polycarbonate |
| Entries | 3x1-1/16" |
| Control | |
| 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 sensors 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 | |
| Adjustable 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' (304m) 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) |
| Environmental | |
| Operating Temperature | -40 °F to 130 °F (-40 °C to 55 °C) |
| Storage Temperature | -67 °F to 167 °F (-55 °C to 75 °C) |
| Approvals | |
| Approval and Area of Use | C-UL-US Listed (non-hazardous locations) |
| Manufacturer | |
| Environmental Technology, Inc. |
| Ordering Information: | |
| 4204-DIS | Automatic Snow/Ice Melting System Snow Switch |
