Danfoss DS-8C Operating guide

LIMITED WARRANTY

The DS-8C is warranted against defects in workmanship and materials for two years from date of sale.
This warranty does not apply to damage resulting from accident, misuse, or alteration nor where connected
voltage is more than 5% above the configured operating voltage, nor to equipment improperly installed or
wired or maintained in violation of this Owner’s Manual. No other written or oral warranty applies. No
employee, agent, dealer or other person is authorized to give any warranties on behalf of DANFOSS.

CAUTION: Read all instructions carefully before installation.
Save this Installation Manual for future reference.

DS-8C

Units returned for warranty repair cannot be modified from shipped condition and leads must protrude a
minimum of 6 inches from the base conduit hub. Repair costs of a modified unit will be quoted as the unit
must be returned to the original, unmodified condition prior to return shipping. The customer shall be
responsible for all costs incurred in the removal or reinstallation and shipping of the product for repairs.
Within the limitations of this warranty, inoperative units should be returned, freight prepaid, to DANFOSS,
and we will repair or replace, at our option, at no charge to you with return freight paid by DANFOSS. It is
agreed that such repair or replacement is the exclusive remedy available from DANFOSS and that
DANFOSS IS NOT RESPONSIBLE FOR DAMAGES OF ANY KIND, INCLUDING INCIDENTAL AND
CONSEQUENTIAL DAMAGE. Some states do not allow the exclusion or limitation of incidental or
consequential damages so the above exclusion may not apply to you. The warranty gives you specific
legal rights, and you may also have other rights which vary from state to state.

DANFOSS ELECTRIC HEATING DIVISIONa
Toronto, Ontario, Canad
TOLL FREE: 866-676-8062

0 PHONE: [phone]

FAX: [phone]

Visit us on the Internet at: www.LX.Danfoss.com

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Intertek

RAIN/SNOW SENSOR CONTROLLER

INSTALLATION MANUAL

AUTOMATED
SYSTEMS

ENCLOSURE TYPE 3R

RAIN/SNOW SENSOR CONTROLLER

CONFORMS TO UL STD 508
CERTIFIED TO CAN/CSA STD C22.2 NO. 14

INPUT
100−277V AC 0.15 A 50/60 Hz
CONTROL
30 A 277V AC, 20 A 28V DC

AVERTISSEMENT: IL PEUT Y AVOIR UN CIRCUIT SECONDAIRE SOUS TENSION

ENGINEERING

DS−8C

DANGER

WARNING: THIS UNIT MAY BE SUPPLIED BY MORE THAN ONE BREAKER

INDICATOR

OFF

POWER

ACTIVATED

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Intertek

3175102

CONTROL SWITCH

MANUAL ON
AUTOMATIC
STANDBY/RESET

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Danfoss Electric Heating Division Toronto, Ontario, Canada

General Safety Instructions

1. THIS UNIT SHOULD BE INSTALLED, OPENED, AND REPAIRED BY QUALIFIED PERSONNEL

ONLY!

CETTE UNITÉ DEVRAIT ÊTRE INSTALLÉE, OUVERTE, ET RÉPARÉE PAR LE PERSONNEL

QUALIFIÉ SEULEMENT!

2. To avoid shock hazard do not open the front cover with power connected to the DS-8C or any controlled

equipment.

Pour éviter la décharge électrique déconnectez toute la puissance avant d'ouvrir la couverture du DS-

8C.

Selecting a Mounting Location for the DS-8C

The small corded device with the interleaved grid is the remote precipitation or "moisture" sensor. The brass cylinder
protruding from the bottom of the DS-8C enclosure is the temperature sensor. For reliable rain and snow detection the
moisture sensor must be exposed to a clear view of the sky. Reference Page 3 "Moisture Sensor Mounting &
Termination" for guidance in mounting the DS-8C moisture sensor. For proper temperature detection the DS-8C
enclosure must be mounted outdoors
powered, the DS-8C moisture grid will always remain hot
melt/evaporate both rain and snow from the grid. The DS-8C enclosure can be mounted by screwing the base conduit
hub onto an appropriate size free-standing conduit or by using the mounting holes in each corner of the enclosure.

DO NOT DRILL HOLES THROUGH THE ENCLOSURE FOR MOUNTING!

NE FONT PAS LES TROUS DE FORET PAR LA BOÎTE POUR LE SUPPORT!

This can allow water into the enclosure causing a potential shock hazard. It is recommended that a weatherproof
junction box be mounted below the DS-8C for termination of the power and load pigtails to the building wiring.

Use Care When Replacing the Front Cover. Do Not Pinch the Gasket or Overtighten the Screws.

CONFIGURATION SWITCH

TEMPERATURE ADJUST

DELAY OFF ADJUST

SENSITIVITY ADJUST

, away from furnace vents, dryer vents, and other sources of heat. Note that, when

CONTROL/MONITOR JACK

. This is normal. This allows the sensor to continuously

GRID TERMINAL

SWITCH JACK

External Control/Monitor Operation

Pin Color Function

1 White GND/Common
2 Red Deice On Mon A
3 Orange Deice On Mon B
4 Black Manual On
5 Green Standby/Reset

monitor relay. This relay, rated at 24 VAC/VDC at 400 ma, will close with the load relay and can be used to
externally monitor activation of the sensor. This terminal block is also the connection point for installing a
CDP-2 interface cable.

The DS-8C provides external control/monitor capability. Shielded
cable rated 300V or higher can be connected to TB2 to access
this feature. Connecting Black (4) to White (1) will activate the
“Manual On” function. Connecting Green (5) to White (1) will
activate the “Standby/Reset” function. See the “Manual Override
Switch Function” for a description of these modes. The
Red/Orange (2/3) leads are connected to an internal low power

Power & Activation Indicator

A green lamp shines through a lens on the c ov er of the DS-8C to indic ate operational s tatus . If this lamp is
OFF the DS-8C is not receiving power. If this lamp is steady ON the DS-8C is powered but is not
triggered. If this lamp is FLASHING the DS-8C is powered on and triggered, the main relay is closed, and
attached equipment should be activated. Note that, even though s now or rain may have stopped, the DS­8C indicator will continue to flash during the Delay-Off drying cycle.

Fine Adjustment for Efficient Operation

The DS-8C is shipped with the TRIG TEMP and DELAY OFF adjustments in the center position,
representing 39°F (3.9°C) and 60 minutes of Delay-Off time respectively. It is also set for highest
SENSITIVITY. Depending on local conditions the user may find that fine adjustment of the controls may
provide more satisfactory operation. If the sensor does not trigger during very wet snows the trigger
temperature may need to be adjusted higher. Constant triggers from snow falling from trees or overhangs
may be reduced by adjusting SENSITIVITY. The Delay-Off time can also be adjusted to provide clean
melt-off without excessive running time. Fine adjustment can both save operating expense and provide
more reliable operation. However, to keep reliability high, always make adjustments in small increments

.

Moisture Grid Maintenance & Replacement

It is recommended that the DS-8C be powered down and the moisture grid wiped clean with clear water at
least once every 4 months. Heavy deposits may be removed using a non-metallic scouring pad (Scotch-

TM

or equivalent.) However, after a number of years, the corrosive elements left behind when water is

Brite
evaporated out of the moisture grid will eventually damage the grid rings. The moisture grid can be easily
replaced by ordering and installing a new MG-3 “Moisture Grid Assembly”. Reference the “Moisture
Sensor Mounting & Termination” section for information on replacing the moisture grid.

INPUT POWER

LOAD

ALWAYS FOLLOW LOCAL AND NATIONAL ELECTRICAL CODES

TOUJOURS SUIVRE LES CODES ÉLECTRIQUES LOCAUX ET NATIONAUX

2

Preseason Snow Detection Testing

It is always a good idea to test the operation of the DS-8C prior to the winter season. Procure some clean
water and, if the outdoor temperature is above the trigger point, a can of spray component cooler (Radio
Shack Part #64-4321 or equivalent.) Clean the moisture grid following the procedure outlined above and
allow it to dry. Apply power to the DS-8C, drip some of the water onto the moisture grid, then, if the
temperature is above the trigger point, spray the temperature sensor protruding from the base of the
enclosure with the component cooler. Once the temperature sensor has reached the trigger point with
water still present on the grid the DS-8C will activate. The user should hear the internal control relay close.
The lamp will blink. Proper operation has been confirmed. Allow the grid to dry completely. To clear the
Delay-Off timer place the override switch into “Standby/Reset”, and then back to the “Automatic” position.

7

LOAD CENTER

CB

240VAC In, 240VAC Load, Heat Cable or Similar

LOAD CENTER

CB

POWER SUPPLY

BROWN

BLUE

POWER SUPPLY

BROWN

BLUE

DS−8C

SWITCHED 240VAC

DS−8C

YELLOW

YELLOW

YELLOW

YELLOW

LOAD

LOAD

Moisture Sensor Mounting & Termination

The DS-8C enclosure and moisture sensor must be
mounted outdoors. The remote DS-8C moisture sensor may

DRIP EDGE

SENSOR

be mounted in a number of ways depending on the application.
The unit operates at low voltage and can withstand immersion
in water. For roof and gutter deicing applications the sensor
head may be mounted in the gutter against the fascia board
with a 1” “C”-style conduit clamp. Allow part of the sensor grid
to be exposed to snowfall. This allows the sensor to initially

GUTTER

trigger when snow starts falling and remain triggered as long as
the roof/gutter heater continues to drip melted snow buildup
from the roof edge when temperatures are below freezing.
Detection can also be achieved by installing the sensor head
near the top of the
downspout using a

DOWNSPOUT

1” conduit hanger
and mounting plate. As water is melted in the gutter it will run
down the downspout, hitting and retriggering the sensor.

Ten feet of cable is pre-terminated to the sensor head. This
cable may be shortened on the controller end as required. Do
not add additional cable to the interface. Erratic operation
may result. Strip the outer insulation and shield from the cable

SENSOR

MOUNTING

PLATE

1" CONDUIT

CLAMP

and terminate each conductor following the color code printed
on the circuit board. The bare drain wire should be installed
into the terminal marked “S” for Shield. Two cable ties are also
included. Wrap these ties securely around the cable in the
enclosure to provide additional strain relief between the flexible
enclosure gland and the free end of the cable.

Setting the Configuration Switches and Adjustments

The following paragraphs and table outline the operating modes for the DS-8C and
explain the functions of the adjustments. Trigger temp (TT) is adjustable from
34°F-44°F (1°C-6°C) using the TRIG TEMP control. When ambient air
temperature (AT) is below this setting precipitation is assumed to be snow. When
above this setting, precipitation is assumed to be rain.

240VAC In, Dry Contact for Boiler/Circulation Pump

These are just some of the possible wiring schemes that can be used to connect the DS-8C to your load for
control. Remember, these are only suggestions

electrician or inspector to assure conformance with applicable local and national
electrical codes!

. You should always consult a qualified

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The DEL configuration switch activates the Delay-Off drying cycle timer on the DS­8C. The timer allows the DS-8C to continue to operate and dry the heated s urface through evaporation

once precipitation has stopped. The drying cycle reduces the chance of
moisture left behind refreezing into ice. This timer is restarted by each
sensor trigger. Therefore, the DS-8C will continue to operate as long as it is
triggered, then for the Delay-Off period once the trigger clears. All "sensor"
modes (DEL Off) provide a 2 minute Delay-Off time. When in "controller"
mode (DEL On) the Long Delay (LD) configuration switch determines the
time span of the drying cycle. The Delay-Off time can be adjusted from 30-

90 minutes (LD Off) or 2-6 hours (LD On) using the DELAY OFF control.

3

The Low Temperature Cutoff (LTC) option is typically used on snow melting systems with limited output
capacity where melting cannot be maintained at very low temperature. If selected, the snow sens or will
clear a trigger below 5°F (-15°C) even if snow is still falling. It will resume
normal operation above 9°F (-13°C). However, the sensor will remember if
it was triggered before the drop below 5°F or if snow was detected during
the cold period. If so, the sensor will execute one Delay-Off cycle when the
temperature rises above 9°F in order to melt any snow left behind during the
cold period. This is referred to as RECOVER

mode. Care should be

exercised in using this mode as the potential exists for ice to be formed
on the melting surface.

The DS-8C precipitation sensor is very sensitive and can detect a single snow flake or rain drop. However,
if the DS-8C is mounted in an area susceptible to high winds, overhanging trees, or blowing ground snow,
nuisance triggering may occur. While proper placement is the best remedy, the SENSITIVITY control can
also be used to reduce nuisance triggering. An internal timer checks the precipitation sensor for moisture
and compares cleared time with triggered time. The highest sensitivity setting (toward MORE) triggers on

first detection. As the control is adjusted clockw ise precipitation must be
detected for a longer period to be considered valid. The lowest sensitivity
setting (toward LESS) requires 120 seconds of detection before the unit
triggers. If a trace amount of snow blows onto the grid from a drift or
overhang it will likely be melted and evaporated in less than a minute.

Similarly, a very light snowfall may also clear quickly from the grid. If these
conditions should be ignored by the sensor the SENSITIVITY control can be adjusted as required.
However, to prevent non-triggering during a true event, it is recommended that the user start at highest

sensitivity (MORE), then adjust while monitoring operation over time.

THE UNIT MUST BE IN STANDBY/RESET TO CHANGE CONFIGURATION SWITCHES

L'appareil doit être en mode STANDBY/RESET pour modifier commutateurs de configuration

Recommended Switch Settings by Function

Function Trigger LD Off LD On LTC DEL RAIN SNOW
Snow sensor w\o LTC TT>AT 2 Min 2 Min OFF OFF OFF ON

Snow sensor w\LTC

TT>AT>5°F
Snow controller w\o LTC TT>AT 30-90 Min 2-6 Hr OFF ON OFF ON
Snow controller w\LTC

TT>AT>5°F
Precipitation sensor Not Used 2 Min 2 Min X OFF ON ON
Precipitation controller Not Used 30-90 Min 2-6 Hr X ON ON ON
Rain sensor AT>TT 2 Min 2 Min X OFF ON OFF
Rain controller AT>TT 30-90 Min 2-6 Hr X ON ON OFF
LT thermostat w\o LTC TT>AT 2 Min 2 Min OFF X OFF OFF
LT thermostat w\LTC

TT>AT>5°F
X = Do Not Care

2 Min 2 Min ON OFF OFF ON

30-90 Min 2-6 Hr ON ON OFF ON

2 Min 2 Min ON X OFF OFF

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Manual Override Switch Operation

An override switch mounted on the side is provided for testing and special operational requirements.
Placing the switch in the AUTOMATIC position will allow the sensor to operate normally, activating the
controlled equipment as needed. Placing the switch in MANUAL ON will close the load relay, activating the
controlled equipment. The “STANDBY/RESET” position prohibits triggering of the unit, clears any active
delay timer, and opens the load relay. In order to reduce excessive runtime for the heater the “Manual

On” mode will remain in effect for up to 40 hours, then return to “Automatic” mode, even if the
switch is still in the “Manual On” position. However, any trigger of the system will restart the 40
hour “Manual On” timer. You may put the DS-8C back into “Manual On” mode by switching to
AUTOMATIC, then back to MANUAL ON. This will also restart the 40 hour timer.

If the override switch is placed in MANUAL ON for less than 2 seconds, then switched back to
AUTOMATIC the controller will execute one Delay-Off cycle. This can be used to clear a frost, hail, or

drifted snow buildup without the danger of leaving the system in a continuous “Manual On” condition.
“Standby/Reset” can still be used to clear this Delay-Off cycle.

Typical Load Wiring

The Yellow load leads are N.O. contacts and do not supply power directly to your load

The relay inside the DS-8C acts as a switch. While not as convenient as directly supplying power for the
load this allows you to operate the DS-8C from one voltage while controlling a load of a different voltage
without adding an external relay or contactor. For example, the DS-8C can be powered from 120VAC but
can directly control a 24VAC signal for a boiler system or 277VAC for heating wire. The following diagrams
show some possible wiring schemes for connecting the DS-8C to your load. Your load may be a direct
connection to heat cable, a heater, a contactor coil, or a control voltage. For clarity the green safety
GROUND leads are not shown.

DS−8C

POWER SUPPLY

BROWN

LOAD CENTER

CB

NEUTRAL BUS BAR

BLUE

SWITCHED 120VAC

120VAC In, 120VAC Load, Heat Cable or Similar (Also Applies To 277VAC)

5

YELLOW

NEUTRAL

YELLOW

LOAD