Difference between 277 single phase and 277/480 3 phase unit?

The difference is the step down transformer that provides the power for the internal circuitry. On the 277 single phase the transformer is 277 VAC to 24 VAC and you will note that its primary winding is connected to the top and middle poles on the...

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Can the APS activate on temperature only?

[The APS-C series systems are designed to turn on and off, as the weather requires heat to deal with snow or icing conditions. Although a thermostatic dry contact switch can be used to override the system on for temperature only, is not recommended...

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External contactors used with the APS-4C?

No, using external contactors will cause the GFEP circuit on the APS-4C to detect the inductive load of the contactors coil as ground fault and alarm the system every time the contactor is turned on. In order to increase the size of the application,...

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Flashing supply light.

A flashing supply light indicates a missing or broken High-Temperature Limit sensor. This sensor is required to make the APS-C series controller to work. It is required on all of the APS-C series controllers.

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Delay between SC-40C and APS-4C?

by David Mays | Jul 26, 2017 |

APS-4C, APS-C Series FAQs, delay, SC-40C

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Why is there a delay between when the APS-4C turns on and when the SC-40C comes on?

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Snow light on SC-40C stays on longer than APS-4C

by David Mays | Jul 26, 2017 |

APS-4C, APS-C Series FAQs, SC-40C, snow, snow light

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The snow light stays on longer for the SC-40C than the APS-4C because the APS-4C gets its command from an actual snow sensor where the SC-40C’s get their command from the APS-4C.

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Is a snow sensor required for a SC-40C?

by David Mays | Jul 26, 2017 |

APS-4C, APS-C Series FAQs, ice, SC-40C, sensor, snow

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No, the SC-40C does not use a snow sensor, it is completely controlled by the attached APS-4C. However, the SC-40C does require the High-Temperature sensor Thermistor to be connected (or bypassed with a 470K-ohm resistor) in order for the unit to...

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Temperature sensor was not installed

The high limit temperature sensor is intended for two purposes, either as a slab sensor when the APS-C series unit is used for heating sidewalks, patios or drives or for ambient air temperature when the unit is used for roof and gutter melt...

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Can I simulate a sensor call for heat?

Yes, you can simulate a sensor call for heat to test the system by putting a jumper between pins 1 and 2 of the class two terminal blocks, the system will respond as if the sensor were seeing snow conditions. The snow and heat indicators will come...

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Snow sensor not detecting snow outside?

There can be several reasons for this. First, start by checking the snow sensor supply voltage between pins 2 and 3 of the class two terminal blocks. It should be close to 24 VDC (the label on some unit incorrectly say 24VAC). If there is no voltage...

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