ASD-4C ASD Controller
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Specifications:
- Model: ASD Controller
- Application: Roof & Gutter Deicing Systems
- Controller Type: ASD-4C, ASD-8C
- Maximum Branch Circuits: 4 for ASD-4C, 8 for ASD-8C
- Maximum Current Capacity: 30A per branch circuit
- Power Supply: 120V, 208V, or 240V
- Timer Function: Available in ASD-8C model
- Listing: ETL Listed Ground Fault Circuit Breakers
Product Usage Instructions:
Installation:
Follow the provided wiring diagrams for ASD-4C or ASD-8C
controllers based on the number of circuits needed.
Operation:
– The ASD Controller switches up to four (ASD-4C) or eight
(ASD-8C) 30A branch circuits.
– When the rocker switch is set to HAND position, heaters are
energized regardless of ambient conditions.
– In the ASD-8C model, an interval timer delays the powering of
specified heater circuits at system startup to reduce overall peak
current.
Ambient RTD Sensor Installation:
– Locate the Ambient RTD Sensor in a typical location, such as
the soffit.
– Ensure proper wiring and connection as per the provided
guidelines.
FAQ:
Q: Can I use extension wiring for remote placement of the
sensor bulb?
A: Yes, you can refer to drawing R50-052-A020 for instructions
on using extension wiring.
Q: How do I adjust the timer settings for local ambient
conditions in the ASD-8C model?
A: The timer’s settings can be field adjusted based on local
ambient conditions. Follow the provided instructions in the manual
for adjusting the ON Delay function.
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ASD Controller
Ambient Sensing for Roof & Gutter Deicing Systems Installation Manual
OVERVIEW
The Raychem ASD Controller is a ETL Listed ambient sensing digital unit that allows on/off operation of Raychem heating cables by energizing up to four (model ASD-4C) or eight (model ASD-8C) branch circuits according to the temperature set points on the digital temperature controller. A set point for heater on/off operation as well as a set point for low temperature cutout of the circuits are provided. The Low Temp Cutout mode serves to save energy by keeping the heaters off when temperatures are so low that no snow and ice melting occurs. Both temperature set points are easily field adjustable to suit local conditions.
DESCRIPTION
The ASD Controller uses a NEMA 4X polyester outdoor enclosure with lockable hasps. Enclosure outside dimensions for each model are: · ASD-4C: 11-1/8″ h x 9-1/4″ w x 5-1/4″ d · ASD-8C: 15-1/4″ h x 13-1/4″ w x 9-3/8″ d
OPERATION
The ASD Controller uses a remote ambient temperature sensor to measure the ambient temperature. When the sensed temperature falls below the Heater On set point, the temperature controller causes the branch circuits to be energized. Conversely, when the sensed temperature raises above the Heater On set point the branch circuits are de-energized. If the sensed temperature falls below the Low Temp Cutout set point, the branch circuits will be deenergized and remain so until the ambient temperature rises back above the Low Temp Cutout set point. A 3-position rocker switch allows the controller to operate in automatic or hand (manual) mode, or to be turned off completely (switch set to the center off position). On the eight-circuit model, an additional timer allows a power on delay (field-adjustable) of four of the eight branch circuits in order to reduce overall heater system peak current. The ambient temperature sensor is mounted outdoors in a shaded location representative of minimum ambient conditions, and away from any heat source, such as a utility room exhaust vent, so that the sensor gives an accurate reading of the actual ambient conditions. The sensor comes with a standard 15 ft lead, but its range can be extended up to hundreds of feet using ordinary stranded copper wire.
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TYPICAL SYSTEM LAYOUT
Cable feed at soffit
Junction Box
(typical)
Cable feed at soffit
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Ambient Sensor (outdoors, shaded, North side of building)
AS-Digital Controller (switches up to four 30A
branch circuits)
Branch Circuit Breaker Panel (GFCB 30mA Trip)
(by others) Indoor Location (garage or similar)
North
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WIRING DIAGRAM ASD-4C CONTROLLER (1 TO 4 CIRCUITS)
To Heater Circuit
To Heater Circuit
To Heating Cable Ground Braid (typical)
A1
A2
A1
A2
1
3
5
7
1
3
5
7
C2
C1
2
4
6
8
2
4
6
8
AUTO OFF HAND
A1 A2 X1 X2
Heater On Indication Light
ASD-4C Controller
Ambient Sensor
Bulb
When rocker switch is set to HAND
position, heaters are energized, regardless of ambient conditions
15 ft Long Sensor Lead
If using extension wiring for remote placement of sensor bulb, refer to drawing R50-052-A020
L N ETL Listed Ground Fault Circuit Breakers (by others) Line Line
120V Supply (Protected Circuit)
208V or 240V Supply
Line Neutral
Sample Wiring
120V or 277V Supply
Field Wiring (by others, typ)
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WIRING DIAGRAM ASD-8C CONTROLLER (1 TO 8 CIRCUITS)
To Heater Circuit
To Heater Circuit
To Heating Cable Ground Braid (typical)
A2
A1
A2
A1
A2
A1
A2
15 A1 B1
7
1
3
5
7
1
3
5
7
1
3
5
7
TRL04
C3
C2
C1
8
2
4
6
8
2
4
6
8
2
4
6
8
A2 16 18
AUTO OFF HAND
A1 A2 X1 X2
Heater On Indication Light
A1
1
3
5
C4
2
4
6
Ambient Sensor
Bulb
When rocker switch is set to HAND
position, heaters are energized, regardless of ambient conditions
15 ft Long Sensor Lead
If using extension wiring for remote placement of
sensor bulb, refer to drawing R50-052-A020
L
N ETL Listed Ground Fault Circuit Breakers
(by others) Line Line
120V Supply (Protected Circuit)
208V or 240V Supply
Line Neutral
Sample Wiring
120V or 277V Supply
Field Wiring (by others, typ)
ASD-8C Controller
THE INTERVAL TIMER IS USED ONLY IN THE ASD-8C MODEL:
In order to reduce heating system overall peak current, the ASD-8C Controller uses an interval timer to delay the powering of specified heater circuits at system start-up. When the ambient temperature falls below the Heater On set point, all heaters wired through contactors C1 & C2 are energized upon call for power from the controller, and the timer begins its programmed ON Delay countdown. Upon completion of the countdown, heaters wired through contactors C3 & C4 are then energized.
ON Delay Function:
15 A1 B1
A2 16 18
Time: .2 (0.2 x Range)
Range: 10m (10 min)
Function: E (ON Delay)
Function E (ON Delay) delays operation of a specified group of heaters for the timer’s specified interval. Two events can initiate this interval period:
1. Control system’s HOA switch is reset from Off or Auto mode to Hand mode.
2. Control system’s HOA switch is set to Auto mode and ambient conditions cause temperature controller to call for heater power. The timer’s settings can be field adjusted for local ambient conditions
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AMBIENT RTD SENSOR INSTALLATION
S o ffit
TYPICAL L O C A TIO N
BWldalgl
Ambient R TD
S ensor
Mounting S crew
Loop (by others) S trap Mounting C lip
15 ft Factory Lead Junction Box
Terminal Blocks (refer to control panel
drawing for proper connections) Temp C ontroller
Note: The NEC (National Electrical Code) allows the routing of control wiring in the same conduit and junction box as the power wiring. The electrical insulation rating on the control wiring must be equal to or greater than the power wiring rating. For example, if the power wiring is 300Vac, then the control wiring leads must be 300Vac rated or greater.
R TD Lead / Extension Wire Field Connections
(route wires to provide physical protection and for aesthetics) Note: When joining the small gauge R TD lead wires to heavier guage extension wires, strip back the insulation far enough to double over the R TD wires.
Control Panel
Copper extension wire, 300 Vac rated insulation:
– 16 gauge up to 60 ft max – 14 gauge up to 120 ft max – 12 gauge up to 240 ft max – 10 gauge up to 480 ft max
Ambient R TD
S ensor
Installation Procedure: 1. Place Ambient R TD Sensor in shaded area
(typically on North side of building under the soffit) away from any heat source (such as solar gain or heated vents) that would create a false (and higher) reading. 2. Place Loop Strap around R TD, between pieces of shrink tube. Secure with a mounting screw (by others) 3. R oute the R TD lead wire to junction box. 4. R oute copper extension wire (note gauge vs length) to the proper terminal blocks in the control panel, as specified in the Control Panel drawing. IMPORTANT: Do not exceed maximum extension wire length versus wire gauge. (refer to listing at left)
AMBIENT TEMPERATURE SENSING WITH LOW TEMP CUTOUT FOR ROOF ICE MELT SYSTEMS ASD CONTROLLER
Heater On Set Value When the ambient temperature falls below the Heater On set value (SEt 1), the Heater On Indication Light will illuminate, indicating that the heater circuits are energized (unless the ambient temperature falls below the Low Temp Cutout set value).
Adjusting Set Values Two set values are available: SEt 1 = Heater On SEt 2 = Low Temp Cutout To toggle between which set value is displayed, press the up arrow. To change the displayed set value, hold down the square button and press the up or down arrow (the longer the arrow button is held down, the faster the value will change).
Heater On Indication Light Low Temp C utout Indication Light (light on indicates low temp cutout is not activated)
Ambient Temperature (PV=Process Value)
Heater On Set Value [SEt 1] (SV=Set Value)
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Low Temp Cutout Set Value
If the ambient temperature falls below the Low Temp Cutout set value (SEt 2), the Low Temp Cutout Indication Light will turn off, indicating that the heater circuits have been de-energized (the Heater On Indication Light remains on). The heater circuits will be re-energized when the ambient temperature rises above the Low Temp Cutout set value.
Note: Low Temp Cutout can be avoided by setting its value below the lowest expected ambient temperature (for example: 150).
Heater On Indication Light Low Temp C utout Indication Light (light off indicates low temp cutout is activated)
Ambient Temperature (PV=Process Value)
Low Temp Cutout Set Value [SEt 2] (SV=Set Value)
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PROGRAM VALUES – AMBIENT TEMPERATURE SENSING WITH LOW TEMP CUTOUT FOR ROOF ICE MELT APPLICATIONS, ASD CONTROLLER
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Default Set Values: 1) Heater On (SEt 1) = 34 2) Low Temp Cutout (SEt 2) = 10
= Manufacturer’s default value. = Programmed value for this
application. Not all parameters shown are available for use on this controller model.
R TD F
150 150
O NF
FD ABS
LOCK LOCK
0.5
Error Display
0.5
Error Meaning
Control Output Status
Sensor break / over range condition
OFF
Sensor reverse / under range condition
OFF
North America
Tel +1 800 545 6258 info@chemelex.com
©2025 Chemelex. All Chemelex marks and logos are owned or licensed by Chemelex Europe GmbH or its affiliates. All other trademarks are the property of their respective owners. Chemelex reserves the right to change specifications without notice.
RAYCHEM-IM-H59371-RIMASD-EN-2504
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Documents / Resources
 |
Raychem ASD-4C ASD Controller [pdf] Installation Guide ASD-4C, ASD-8C, ASD-4C ASD Controller, ASD-4C, ASD Controller, Controller |