What is the difference between the APS 277 single phase unit and the 277/480 three phase unit?
The difference is the step down transformer that provides the power for the internal circuitry. On the APS 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 contactor. On...
Can I use the APS-4C to drive external contactors for more circuits?
No. Doing so will cause the GFEP circuit on the APS-4C to detect the inductive load of the contactor coil as ground fault and alarm the system every time the contactor is turned on. The APS-3C is designed without an internal GREP circuit so it will work with external...
Is there a way to make the system come on with 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 alone, is not recommended since it will...
Why is there a delay between when the APS-4C turns on and when the SC-40C comes on?
This delay between the APS-4C and the SC-40C is programmed into the system in order to reduce surge current. When the heaters are turned on they will have a large inrush of current for a few seconds. If all the heater circuits came on at the same time the inrush...
Why does the snow light go off on the APS-4C but remain on for the SC-40C’s?
The snow light goes off on the APS-4Cbecause the APS-4C gets its command from an actual snow sensor where the SC-40C’s get their command from the APS-4C. When the snow sensor’s moisture grid dries out, it no longer sends a snow present command to the APS-4C so it’s...
Do I need to attach a snow sensor to the SC-40C?
No. The SC-40C satellite contactor does not use a snow sensor, it is primarily controlled by the attached APS-4C control panel. A manual heater cycle of the SC-40 satellite contactor can be initiated from its front panel or from an optional RCU-4 remote control.
What is the EMC light for?
EMC stands for Energy Management Computer, which can used to remotely monitor and control the APS C series ice melt controllers. These connections are made to the Class 2 connection terminal block on pins 14 through 22. The following diagram will aid in making these...
How do I connect my SC-40C to my APS-4C?
These connections are done on the Class 2 terminal blocks on both units as follows: APS-4CPin SC-40C Pin Next SC-40C Pin 4------------------------------ 4 ------------------------------ 4 6...
Why is the GFEP light flashing on my APS-4C?
This indicates that there is a ground fault on one of the attached SC-40C satellite controllers. The SC-40C that has the ground fault will have a solid red GFEP light and will not allow the heaters to be powered. Isolating the heater leg that has the ground fault is...
Why do I have a red GFEP light on?
The GFEP indicator will come on when a ground fault occurs in one of the heater circuits. The insulating resistance of the heater cable is breaking down or the cable has been damaged allowing current to pass to ground thru an incorrect pathway. Left un-repaired the...
How do I simulate a sensor call for heat to test my snowmelt/deicing system?
There are two basic way to test a system to ensure that the control(s) will work when snow and/or ice are detected. The first way is to simulate the conditions required for operation. Lower the temperature of the sensor if it is not cold enough out and then get the...
When my APS C series control panel was installed the high temperature sensor was not installed, can I still make the unit work?
The high temperature limit sensor is intended for two purposes, either as a slab sensor when the APS C series unit is used for heating side walks, patios or drives or for ambient air temperature when the unit is used for roof and gutter melt systems. In roof and...
Why doesn’t adjusting the High Temperature Limit dial turn on my APS C series control panel?
The high temperature limit dial is used to set the maximum temperature that the unit will work at. When the High temperature limit sensor detects a temperature higher than what is selected on the dial it overrides the system and shuts it off. This function can be used...
Why is the supply light flashing on my APS C series control panel?
A flashing supply light indicates a missing or broken High Temperature Limit sensor. All APS C series control panels include a temperature sensor for measuring pavement slab or ambient air temperature. Its signal is used to provide an adjustable high limit thermostat...
Snow Switch Sensors & Controls
Snow Switch sensors and controls have provided over 40 years of dependability and experience. Systems up to 16 amps typically use an LCD–7 controller, integrating sensing and power switching for cost effective deicing of small applications.