Danfoss DS-224, DS-824 Data sheet

DANFOSS DS-224/824
Hydronic Snow Melt Controllers/Sensors

Advanced, Low Voltage and Intuitive

The DS Controllers are primarily designed for
hydronic snow melting applications. The
DS224 has built in moisture and temperature
sensor while the DS824 has a built in
temperature sensor and a remote mount
moisture sensor (10ft. lead). The units can be
powered from a 24VAC/VDC source.

The DS Controllers feature a new Trigger
Sensitivity Adjustment. The sensitivity
adjustment allows setting the number of
seconds the precipitation grid must see
continuous rain or snow before the sensor is
triggered and ranges from 3 seconds to 4
minutes. A higher sensitivity setting assures
quick detection no matter the conditions. A
lower sensitivity setting will allow a few stray
drops of rain or flakes of snow to be ignored
but a heavier downfall will trigger the system.

HYDRONIC SNOW MEL

T CONTROLLER

Features:

Designed for Low Voltage Hydronic and



Battery Powered Systems

Automatic Activation = Lower Deicing Costs

Reliable Rain and Snow Detection

24VAC/VDC Operation, Only 20 VA Required

Replaceable Precipitation Sensor

Easy Installation, Full Access to Electronics

8 Different Functions

Adjustable Temperature Trigger Point

Adjustable Delay Off Cycle, Selectable 30-90

Mins or 2-6 Hrs

Selectable Low Temperature Cutoff

Smart "Manual On" Operates for One Delay

Off Cycle

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Toll Free: 866-375-HVAC (4822)

Dimensions

4¾"(120) x 7"(178) x 2¾"(70)

Weight

2 Lbs. (0.9 Kg)

Ambient Temperature

-40°F to +185°F (-40°C to +85°C)

Enclosure Rating

NEMA 3R

Supply Power

22-28VAC/VDC 15VA maximum, 5VA typical

Trigger Temperature

34°F-44°F (1.1°C-6.6°C) Field Selectable

Delay Off (Sensor)

2 Minutes

Delay Off (Controller)

30-90 Minutes/2-6 Hours Field Selectable

Load Contact Capacity

30A @ 24 VAC/100,000 operations minimum at full load

Remote Control and
Monitor Contact Capacity

24 VDC/VAC 400mA 10W total

DS-224/824 Specifications

Function

Ambient Temp (AT)

Delay Off (LD Off)

Delay Off (LD On)

Suggested Application

Snow sensor w\o LTC

AT < T T

2 Min

2 Min

Snow and ice alert, Sensor for external deice/snow melt controller (unlimited heat)

Snow sensor w\LTC

TT>AT>15°F (9.5°C)

2 Min

2 Min

Sensor for external deice/snow melt controller (limited heat)

Snow controller w\o LTC

AT < T T

30-90 Min

2-6 Hrs

Stand-alone controller for electric/hydronic snow melting

Snow controller w\LTC

TT>AT>15°F(9.5°C)

30-90 Min

2-6 Hrs

Stand-alone controller for electric/hydronic snow melting

Part Number

Description

088L3041

DS-224 Hydronic Snow Melt Controller

Part Number

Description

088L3042

DS-824 Hydronic Snow Melt Controller with 10 ft. sensor cable*

Typical Wiring

Technical data

The DS Controllers can be powered from a 24VAC/VDC source. An environmentally sealed control switch is provided. The "Manual
Peak power consumption is 15 VA at startup, 8.5 VA steady On" function activates the controlled equipment for testing and
state triggered, 5 VA steady state untriggered. Power input is special operational conditions. The "Automatic" position allows the
polarity protected for a DC supply. The unit provides a single DS Controllers to handle all detections and control. The
24VAC/30A or 24VDC/20A normally open dry contact. This "Standby/Reset" position disables triggering and can also be used
contact is paralleled with a low power contact set to provide to clear the delay off timer (see below) from true or test activation.
remote control and activation monitoring. Operational If the switch is placed in "Manual On" for less than 2 seconds, then
temperature range is -40°F to 185°F (-40°C to +85°C). switched back to "Automatic" the controller will execute one delay

off cycle. This allows a controlled manual activation of the snow
Trigger Temperature (TT) is adjustable from 34°F to -44°F melt system without the fear of forgetting and leaving the system
(1°C to -42°C) using an on-board control. When ambient air in "Manual On" for an extended and potentially very expensive
temperature (AT) is below this trigger point precipitation is period of time. "Standby/Reset" can still be used to clear this delay
assumed to be snow or freezing rain. When above the trigger off cycle.
point, precipitation is assumed to be rain.

The Low Temperature Cutoff (LTC) option is typically used on
"Delay Off" refers to the internal drying cycle timer of the deicing or snow melting systems with limited output capacity. If
DS Controller. The timer is used to allow the DS Controllers to selected, the sensor will not trigger if precipitation is detected
dry the heated surface through evaporation once below 15°F (-9.5°C). However, if the deicing system has been
precipitation has stopped. The drying cycle reduces the activated, precipitation continues, and the ambient temperature
chance that moisture left behind by the melting process will drops below 15°F (-9.5°C), LTC will be ignored. This assures that
re-freeze into ice. This timer is restarted by each precipitation water left behind on the surface during the heating cycle will not
detection. Therefore, the DS Controllers will continue to immediately re-freeze into ice as a result of deactivating the
operate as long as precipitation and trigger temperature is deicing system.
detected, then for the "Delay Off" time once rain or snow
stops. It is assumed that, when operating as a sensor, the The DS Controllers feature a new innovation, a Trigger Sensitivity
controller is supplying an activation signal to an external Adjustment (TSA). The sensitivity adjustment allows setting the
control system. All "sensor" modes provide a minimum 2 number of seconds the precipitation grid must see continuous rain
minute closure, reducing cycling of the external controller. The or snow before the sensor is triggered and ranges from 3 seconds
Delay Off cycle has been extended for hydronic applications to 4 minutes. A higher sensitivity setting assures quick detection
and is determined by the Long Delay (LD) switch setting, DEL no matter the conditions. A lower sensitivity setting will allow a
switch setting and the DEL adjustment. Delay Off is 30-90 few stray drops of rain or flakes of snow to be ignored but a
minutes in non-LD "controller" mode and 2-6 hours in LD heavier downfall will trigger the system.
"controller" mode.

Ordering Information

Danfoss

Toll Free: 866-375-HVAC (4822)
Phone: [phone]
Fax: [phone]
www.na.heating.danfoss.com

Copyright 2010 Danfoss

*Can be extended up to 30 feet with four-conductor #18 AWG shielded cable

Danfoss

Toll Free: 866-375-HVAC (4822)
Phone: [phone]
Fax: [phone]
www.na.heating.danfoss.com

NA.HH.DS224/824