Danfoss Roof application. Frost protection Application guide

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Roof application. Frost protection

Application manual

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Danfoss Roof application. Frost protection Application guide

Index

1. General information	4
2. System Description	5
3. Product Selection	6
4. System Design	9
5. Installation	12
6. Cases	24

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Along with full compliance with EU directives and product approvals

Let DEVI do the work

DEVI - an abbreviation of Dansk El-Varme Industri - was established in Copenhagen, Denmark, in 1942. As from January 1st 2003 DEVI has become a part of the Danfoss Group - Denmark’s largest industrial Group. Danfoss is one of the world’s leading companies within heating, cooling and air-

conditioning. The Danfoss Group has more than 23000 employees and serves customers in more than 100 countries.

DEVI is Europe’s leading brand of electrical cable heating systems and electric pipe heating systems with over 70 years of experience. The production of heating cables takes place in France and Poland while the head office is situated in Denmark.

The value of experience

We have installed literally thousands of systems across the globe, in every conceivable setting. This experience means that we can offer you practical advice about precisely which components you need to get the best results at the lowest cost.

Roof application. Frost protection

This design guide presents DEVI’s recommendations for design and installation of ice and snow melting systems for roofs application.

It provides guidance for heating cable positioning, electrical data and system configurations.

Following DEVI’s recommendations will ensure energy efficient, reliable and maintenance free solution for constant wattage heating cables with

20 year warranty.

1. General information

DEVI’s ice and snow melting system for roofs and roof gutters can be applied for virtually any type of roof constructions to prevent meltwater accumulation in roof gutters and to reduce damage to constructions like frozen facades and roofs.

The ice and snow melting system should be installed along the roof edge or where there is a risk of ice and snow formation. Damage prevention in roof gutters and downpipes is achieved by efficient and free meltwater draining, which typically proves satisfactory operation of the system.

Electronic DEVIreg™ thermostats ensure that optimal results are achieved with the least possible energy consumption. These results are ensured by highly precise readings of weather sensors and thermostats providing automatic on/off heating control at the right time.

The typical applications are roof constructions, roof gutters, downpipes, flat roofs and valley gutters.

Benefits

•Enter and exit the building safely – no risk of icicles formation or falling in cold season causing injuries or damage to vehicles or other property.

•Relief of roof constructions – reduces the risk of roof collapse due to extra snow loads or roof gutters and downpipes damage due to ice loads.

•Cost reduction for renovation following the winter season – by keeping facade walls dry as the DEVI system ensures safe water evacuation from the roof during the cold season.

•Maintenance-free solution

with 20-year full warranty on constant wattage heating cables includes product price and all related repairing costs.

•Cost-effective & Energy-saving solution – designed for various weather conditions with automatic operation based on 24-h monitoring and ice

and snow removal, it ensures payback period of just one snowy winter.

4 Roof application. Frost protection · VGLUE102 · ©DEVI

2. System Description

When winter sun melts snow and ice, it starts forming icicles on cold roof edges and gutters which over time can cause serious damage

to the building and constitute a danger for vehicles and passerby.

First of all, in order to avoid all above and manual ice removal heating cables should be installed in all drains such as gutter valleys, gutters and downpipes.

Frost protection of the roof itself is required where such problems can exist, e.g:

•on south-faced eaves

•under skylights/roof windows

•1-1.5 m lower the roof for older houses, e.g. with heated attics and

•on roofs where snow loads typically exceed the capacity of the existing roof construction.

In harsh water or water and sludge environment DEVIsnow™ cables provide constant wattage when appropriate, whereas DEVIiceguard™ self-limiting cables represent flexible small scale installation.

Opportunities

•No winter damage costs

•Discreet UV resistant cables

•Automatic control

•Priority zones with limited power supply

Installation

DEVIsnow™ 20, DEVIsnow™ 30 W/m DEVIsnow™ 30 for roofing felt DEVIiceguard™ for small scale

solutions (< 10 m) DEVIclip™ fixing accessories DEVIfast™ fitting band

Performance

Save 50-80% with control by smart DEVIreg™ 850.

Thermostat improves DEVIiceguard™ performance with regard to energy consumption.

Roof edge / Eave	Gutter valley	Flat roof with drain	Roof with baffles
DEVIclip™ Roof Hook	DEVIfast™ & DEVIfast™ Double	DEVIfast™ & DEVIfast™ Double	DEVIfast™ & DEVIfast™ Double
DEVIclip™ Guard Hook	DEVIclip™ C-C		DEVIclip™ C-C
DEVIfast™ & DEVIfast™ Double

Gutter	Downpipe to frost-free well	Downpipe with open end
DEVIclip™ Gutter	DEVIclip™ Traverse	DEVIclip™ Relief
DEVIfast™	DEVIfast™ Double	DEVIfast™ Double
	Chain / Entlastungseil	Chain / Entlastungseil

Roof application. Frost protection · VGLUE102 · ©DEVI 5

3. Product Selection

3.1 Heating elements

Heating cables DEVIsafe™ 20T and DEVIsnow™ 30T:

Heating cable DEVIsafe™ 20T/ DEVIsnow™ 30T – a twin conductor resistive heating cable complies with IEC 60800:2009 and provides high UV resistance. Ready-made set with a connection box and 2,5 m cold lead. Cable design provides for 230 V and 400 V power supply and ensures installation in a safe, efficient and cost-saving manner.

Heating cable DEVIiceguard™ 18:

Heating cable DEVIiceguard™ 18 is a self-limiting parallel heating cable (SLC) with high UV resistance. The cable can be cut to the required length from drum or ready made (RM) version.

The self-limiting capability of the cable ensures that the output of the cable increase or decrease according to the ambient temperature.

DEVIsafe™ 20T/DEVIsnow™ 30T

3.2. Control

Frost protection systems are different and require different thermostat types.

DEVIreg™ thermostats are fitted with a complete set of control functions for heating systems for ice and snow melting of any

type and allow attaching external measuring sensors for air or ground temperature measuring as well as control of moisture conditions.

Electronic thermostats feature high-speed operation and good repeatability. Correctness of thermostat selection and control accuracy impact significantyly on reliability and power consumption of the heating system.

The thermostat product range is designed for external systems

including the following: DEVIreg™ 316, DEVIreg™ 330, DEVIreg™ 610 and DEVIreg™ 850.

DEVIreg™ 850 electronic controller

Two-zone controller is recommended for the installation protection against frost.

It has external 24 V DC power supply. Four integrated roof moisture and temperature sensors can be connected to the controller providing optimal control of the heating system. Comparing to installations with

DEVIreg™ 850

Moisture roof sensor

The heating cable is flexible and easy to install as it can be cut to length in situ and can be installed directly on the roof or in the gutter system.

Important: Always install thermostat over 3 m far from the self-limiting cables, this will help to prolong cable lifetime and minimize energy consumption in a standby mode.

DEVIiceguard™ 18

typical temperature measuring this thermostat allows reducing energy consumption costs of up to 75% (see 3.2.1).

Moisture and temperature roof sensor

Moisture and temperature measuring sensor with a built-in heating element for snow melting. All measured values are highly accurate, which is provided by an integrated processor of the sensor as well as digital, not analogous, measurment and set-point calculation. The sensor is equipped with a 15 m cable for connection to the controller.

DEVIreg™ 316, DEVIreg™ 610

3.2.1 DEVIreg™ 850 detailed description

DEVIreg™ 850 microprocessor controller is fully automatic, digital electronic device. Its operation is based on complex digital measurements provided by temperature and humidity measuring sensors. Simultaneous moisture and temperature

measuring allows controller to save up to 75% energy comparing with systems that provide temperature measurements only.

Digital sensors provide much higher accuracy than analog ones. As a result frost protection system operated by DEVIreg 850™ provides higher level of functionality and lower operating costs. Therefore we recommend using this type of thermostat for installations with output capacity exceeding 5 kW or for any smaller installations where optimum power use is a preference.

Configuration options

DEVIreg™ 850 can control two independent installations with maximum 4 sensors connected in various configurations, i.e. two independent systems or two

zones in one system with separate outputs.

In addition, priority setting for both zones is possible. You can set one zone for the higher priority and another for the lower priority.

The zone with lower priority will be activated following switching off the zone with higher priority. In this way you can reduce demand of the available power for the frost protection system.

Intuitive menu of the thermostat allows simple settings. For detailed instructions and data specifications please refer to the safety data catalog and installation manuals for corresponding sensors and controllers.

Note: When connecting more than two sensors additional power supply is required.

Energy consumption

Сontrol of several parameters has an effect on energy consumption.

No energy is consumed in cold dry weather – usage of moisture sensors is important and enables switching the system off in cold dry days, so no excessive energy is consumed.

Less energy consumption in case of system splitting into zones with different weather impact – splitting area into 2 zones, e.g. North and South, allows saving energy when the southern side is free of ice and snow melting runs faster by the sun heat.

Running hours for different control systems - Example from Salzburg, Austria, winter 2005/2006.

Controller	Sensor parameters		Origin of data	Hours	Index

DEVIreg 850™	Air temperature below +3	°C and moisture	Meter reading	535	1

DEVIreg 316™	Air temperature between +3 °C and -7 °C		Weather data	2309	4

DEVIreg 330™	Air temperature below +3	°C	Weather data	2737	5

None	Constant from November to March			3624	7

* DEVIreg™ 850 is a highly efficient multizone thermostat which is equipped with a multilingual menu enabling both temperature and humidity measuring as well as zone prioritization in case of limited power.

3.3 Accessories

Roof and drain pipes plastic fixings, plastic tape for roof drains:

Plastic material with increased UV resistance.

Allows quick and easy installation of cables intended for heating roof areas with an installed protection system.

DEVIclip™ Guardhook, Roofhook,

RX-C Roof Clip:

Enable non-invasive installation of heating cables in tracts and areas adjacent to roof gutter edge.

Self-limiting accessories

Refer to Installation of self-limiting cabels.

DEVIclip™ C-C

DEVIclip™ Roofhook, Gutter, Guardhook

3.4 Product selection general overview table

Galvanized steel chain for drain pipes and DEVIfast™ Double:

Corrosion-resistant hot-dip galvanized steel chain for cable installation in downpipes.

DEVIfast™ Double

Product	Options	Description

DEVIsnow™	DEVIsnow™ 20T (with roofing felt)	Twin conductor cable, 100%
DIN IEC 60800,	DEVIsnow™ 30T	screen, UV stabilized, black
Constant wattage;	230 & 400 V program

DEVIsafe™	20T	Twin conductor cable, 100%
DIN IEC 60800,	230 & 400 V program	screen, UV stabilized, black,
Constant wattage;

DEVIiceguard™	DEVIiceguard™ 18T	Twin conductor cable, wire
DIN VDE 0254	Drum & Ready made program	screen, UV stabilized black
Self-limiting cable

Thermostat	DEVIreg™ 850 with air & moisture sensor	2x15 A, 24 V PSU, DIN rail
	DEVIreg™ 316 with min/max temp.	-10...50 °C, 16 A, DIN rail
	setting	-10...10 °C, 16 A, DIN rail
	DEVIreg™ 330, max. temp. setting	-10...50 °C, 10 A, wall intallation
	DEVIreg™ 610, max. temp. setting

Sensor	Roof sensor for Devireg™ 850	IP67 with 15 m sensor cable
	Air sensor for Devireg™ 316 & 330	IP44, 15 kΩ

Accessories	DEVIfast™ Metal	C-C steps 2,5 cm
	DEVIfast™ Copper	C-C steps 2,5 cm, in copper
	DEVIclip™ C-C	C-C steps 1 cm
	DEVIclip™ Gutter	C-C steps 1 cm for gutters only
	DEVIclip™ Roof Hook	Hook for roof edges
	DEVIclip™ Guard Hook	Hook for snow fence
	DEVIclip™ Traverse	For downpipe hole
	DEVIfast™ Double	For cable loop in downpipe
	Spaceclip	SLC Relief for sharp edges
	Extra 24 V PSU for Devireg 850	Needed with 3-4 sensors

For self-limiting cables	DEVIchain™
	DEVIdrain™
	Connection box
	Connection box kit
	Cold tail connection kit
	End termination
	Connectors

+ 16 hidden pages