Raychem EM-MI Installationsguide

EM-MI

EM-MI Snow Melting System for Asphalt Ramps

System EM-MI

Freiflächenbeheizung Für Asphaltflächen

Système EM-MI

Le Traçage Électrique Pour Voies D’accès En Asphalte

EM-MI

Varmesystem For Asfaltramper

EM-MI

Värmesystem För Asfaltytor

EM-MI

Asfalttipinnoitteisten Ulkoalueiden Sulanapito

System EM-MI

System Grzewczy Dla Podjazdów I Ramp O Nawierzchni

Asfaltowej

EM-MI

1 EM-MI

Installation and Operation Manual 6

2 System EM-MI

Montage- und Betriebsanleitung 22

3 Système EM-MI

Guide d’installation et de mise en service 36

4 EM-MI

Monterings- og driftsanvisninger 51

5 EM-MI

Installations- och driftmanual 66

6 EM-MI

Asennus- ja käyttöopas 81

7 System EM-MI

Instrukcja montażu i uruchomienia 96

nVent.com | 3

1.

5

1

4

7

105

6

11

12

13

14

3

2

8

9

15

Designation Heating cable dia.

(mm)

Resistance (± 10%)

at 20°C (Ω)

230 V AC Circuit breaker

(C-characteristic)

Bezeichnung Heizkabel (mm) Widerstand (± 10%)

bei 20°C (Ω)

AC 230 V Leitungsschutzschalter

(C-Charakteristik)

Référence Câble chauffant (mm) Résistance (± 10%)

à 20°C (Ω)

Disjoncteur (courbe C) 230 VAC

Betegnelse Varmekabel (mm) Motstand (± 10%)

ved 20°C (Ω)

AC 230 V automat-sikring

(C-type)

Beteckning Värmekabeldiameter

(mm)

Resistans (± 10%)

vid 20°C (Ω)

AC 230 V VAC avsäkring (karakteristik C)

Nimitys Lämpökaapelin

halkaisija (mm)

Resistanssi (± 10%)

20°C:ssa (Ω)

230 V AC:n johdonsuoja-

katkaisija (tyyppi C)

Oznaczenie zestawu Przewód

grzejny (mm)

Rezystancja (± 10%) przy

20°C (Ω)

AC 230 V Wy∆åcznik nadmiarowy

(charakterystyka C)

EM-MI-PACK-26M Ø 4,8 41,6 10 A

EM-MI-PACK-36M Ø 4,9 28,8 10 A

EM-MI-PACK-48M Ø 5,5 21,6 13 A

EM-MI-PACK-60M Ø 6,0 18,9 16 A

EM-MI-PACK-70M Ø 5,9 15,4 16 A

EM-MI-PACK-88M Ø 6,3 12,3 25 A

4 | nVent.com

Heating system

1. nVent RAYCHEM EM-MI heating cable

2. Connection lead

3. Spacer nVent RAYCHEM VIA-SPACER

4. Control unit temperature and moisture

sensor

5. Junction box

6. Connection lead conduit

7. Sensor lead conduit

8. Control panel with residual current

device (RCD 30 mA), circuit breaker

(C-characteristic) and output contactor

9. Control unit nVent RAYCHEM VIA-DU-20

10. Supply lead

Drain tracing system

11. Junction box nVent RAYCHEM JB16-02

12. Connection kit nVent RAYCHEM C25-21

13. Heating cable nVent RAYCHEM 8BTV2-CT

14. End seal nVent RAYCHEM E-06

15. Supply lead

Freiflächenbeheizung

1. Heizkabel nVent RAYCHEM EM-MI

2. Anschlusskabel

3. Abstandhalter nVent RAYCHEM VIA-SPACER

4. Temperatur- und Feuchtefühler der

Steuerungseinheit

5. Anschlusskasten

6. Schutzrohr für Anschlusskabel

7. Schutzrohr für Fühlerkabel

8. Schaltschrank mit

Fehlerstromschutzschalter (RCD 30 mA),

Leitungsschutzschalte (C-Charakteristik)

und Leistungsschütz

9. Steuerung nVent RAYCHEM VIA-DU-20

10. Zuleitung

Rinnenbeheizung

11. Anschlusskasten

12. Anschlussgarnitur

13. Heizband nVent RAYCHEM 8BTV2-CT

14. Endabschluss

15. Zuleitung

Traçage de la rampe

1. Câble chauffant nVent RAYCHEM EM-MI

2. Câbles de liaison froide

3. Bande de fixation et d’écartement nVent

RAYCHEM (VIA-SPACER)

4. Sonde d’humidité et de température de

l’unité de commande

5. Boîtier de raccordement

6. Tube de protection pour câble de liaison

froide

7. Tube de protection pour câble de sonde

8. Armoire électrique avec disjoncteur

différentiel (RCD 30 mA), disjoncteur (courbe

C) et contacteur de puissance

9. Unité de commande

10. Câble d’alimentation

Traçage du drain

11. Boîtier de raccordement nVent RAYCHEM

JB16-02

12. Kit de connexion nVent RAYCHEM C25-21

13. Ruban chauffant nVent RAYCHEM 8BTV2-CT

14. Terminaison nVent RAYCHEM E-06

15. Câble d’alimentation

Oppvarmingssystem

1. nVent RAYCHEM EM-MI varmekabler

2. Tilkoplingskabel

3. Avstandsholder

4. Styringsenhet med temperatur- og

fuktighetsføler

5. Koplingsboks

6. Rør til tilkoplingskabel

7. Rør til følerkabel

8. Koplingsskap med jordfeilbryter

(RCD 30 mA), kretsbryter (av typen C)

og overspenningsvern

9. Styringsenhet

10. Tilførsel

Varmesystem for avløp

11. Koblingsboks

12. Tilkoblingssett

13. Varmekabel nVent RAYCHEM 8BTV2-CT

14. Endeavslutningssett

15. Kaldkabel

nVent.com | 5

Värmesystem

1. nVent RAYCHEM EM-MI värmekabel

2. Anslutningskabel

3. Fästband, rutarmering etc

4. Markgivare, temperatur- och fukt

5. Kopplingsdosa

6. Skyddsrör för anslutningskabel

7. Skyddsrör för givarkabel

8. Apparatskåp med jordfelsbrytare (RCD

30 mA), (30 mA), avsäkringar (typ C) och

utmatning

9. Kontrollenhet

10. Matarkabel

Värmesystem för avloppsledningar

11. Kopplingsdosa

12. Anslutningssats

13. Värmekabel nVent RAYCHEM 8BTV2-CT

14. Avslutningssats

15. Matarkabel

Lämmitysjärjestelmä

1. nVent RAYCHEM EM-MI -lämpökaapeli

2. Kylmäkaapeli

3. Kiinnitysnauha

4. Ohjausyksikön lämpö- ja

kosteusanturi

5. Kytkentärasia

6. Kylmäkaapelin suojaputki

7. Anturijohtimen suojaputki

8. Keskukset vikavirtasuojakytkimillä

(30 mA), johdonsuojakatkaisija

(tyyppi C) ja kontaktorit

9. Ohjausyksikkö

10. Syöttökaapeli

Viemärin lämmitysjärjestelmä

11. Kytkentärasia

12. Rasiapääte

13. Lämpökaapeli nVent RAYCHEM 8BTV2-CT

14. Loppupääte

15. Syöttökaapeli

Ogrzewanie podjazdu asfaltowego

1. Przewód grzejny nVent RAYCHEM EM-MI

2. Przewód przy∆åczeniowy

3. Listwa dystansowa

4. Czujnik temperatury i wilgotno∂ci uk∆adu

sterujåcego

5. Puszka przy∆åczeniowa nVent RAYCHEM

VIA-JB1

6. Rurka ochronna przewodu

przy∆åczeniowego

7. Czujnika przewodu

8. Panel sterowania z wyłącznikiem różnicowo-

prądowym (RCD 30 mA), wyłącznikiem

(typ C) i wyjściem

9. Sterownik nVent RAYCHEM VIA-DU-20

10. Przewody zasilajåce

Ogrzewanie odwodnienia liniowego

11. Puszka przy∆åczeniowa nVent RAYCHEM

JB16-02

12. Zestaw przy∆åczeniowy nVent RAYCHEM

C16-29

13. Przewód grzejny nVent RAYCHEM 8BTV2-CT

14. Zestaw zakoµczeniowy nVent RAYCHEM

E-06

15. Przewód zasilajåcy

6 | nVent.com

General

Important

All the instructions provided in this manual must

be followed carefully to ensure that the heating

system operates correctly. The installation must

also be compatible with local requirements

applicable to electrical heating systems. The

presence of the trace heating shall be made

evident by the posting of caution signs or

marking where clearly visible.

Warning

The EM-MI heating cables in the EM-MI system

are electrical devices which must be designed

and installed correctly. Follow all design,

installation, test and operating instructions to

ensure proper operation and to prevent electrical

or fire hazard. De-energize all power circuits

before installation or servicing. Ensure that the

ends of the heating cable unit are kept dry at all

times.

Scope

This manual focuses on the installation of EM-MI

heating cables in asphalt designed for long-term

structural stability. nVent can supply a different

series of suitable products for laying in concrete

or for other applications.

Laying spacing

A

B

Concrete

Asphalt

Power Laying

spacing A

Depth below surface B

180 W/m

2

275 mm min 25 mm , max 75 mm

300 W/m

2

165 mm min 25 mm , max 75 mm

The prestamped metal strips (VIA-SPACER) will

help you to maintain the correct laying spacing.

NVENT RAYCHEM EM-MI RAMP HEATING SYSTEM

INSTALLATION AND OPERATION MANUAL

General 5

EM-MI Ramp Heating System 6

Additional Items 7

Preparing the Substratum 7

Pre-Installation Checks 8

Layout Considerations 9

Heating Cable Installation 11

Check the Installation 15

Asphalt Pouring 15

Drain Tracing System with Self-Regulating Heating cable 8BTV2-CT 16

Finishing 18

Operating 18

Trouble Shooting Guide 20

nVent.com | 7

EM-MI Heating Cable with Connection

Leads

The EM-MI heating cable (1) provides even heat.

It consists of a metal conductor surrounded by

mineral insulation.

The conductor and the insulation are protected

from mechanical damage by a copper jacket with

a non-PVC outer jacket.

The EM-MI heating cable is supplied ready for

installation with “cold” connection leads (2) at

both ends. Keep ends of trace heaters and kit

component dry before and during installation.

Each connection lead comprises a short, rigid

length and 3 m of flexible cable connected

directly to the control panel. A conduit (supplied

on site) protects the flexible length of cable and

the crossover from the rigid to the flexible cable

from contact with the asphalt. The flexible cable

is provided with braid for earthing.

Spacer (3), Junction Box (5)

and Supply Lead (10)

The purpose of the spacers is to hold the MI

heating cable in place and to enable a regular

laying spacing to be maintained. Extension of

the cold connection leads needs to be done in a

junction box. The connection between the control

panel and the junction box is made by a suitable

supply lead.

Controller (9)

nVent offers control units specially designed

for snow and ice melting applications. They

incorporate combined temperature and moisture

sensors to ensure efficient operation of the

system.

Panels (8)

nVent offers a range of standard panels

specifically designed for ramp heating

applications. Each panel contains a built in

control unit, plus circuit breakers and residual

current devices (RCDs).

3 m

5–20 cm

Flexible

connection lead

Crossover with

flexible / rigid cable

Rigid cable Crossover with rigid /

MI heating cable

No asphalt or in conduit Asphalt

EM-MI HEATING SYSTEM

THE EM-MI SYSTEM COMPRISES THE FOLLOWING ITEMS:

8 | nVent.com

ADDITIONAL ITEMS

Conduits (6,7)

Conduits (supplied on site) are required to

protect the

• flexible connection lead and crossover with

the rigid/flexible connection lead

• sensor connection lead.

Electrical Control Equipment

If nVent standard panels are not used, further

items will be required to complete the system:

• contactors

• circuit breakers

• residual current device (RCD) 30 mA. (Multiple

heating cable circuits up to a total length of

167 m may be protected by a single 30 mA

RCD).

• One 300 mA RCD can be used to protect up

to 1500 m EM-MI heating cable. Note, though,

that drain tracing must be protected by a 30

mA RCD in all cases.

Storage

• Storage temperature range: –40°C to +60°C

• Store all system elements in a clean, dry

place.

Equipment

• 1000 Vdc insulation resistance tester (min.

500 Vdc)

• Multimeter

PREPARING THE SUBSTRATUM

The heating cable is normally laid on firm

substratum. In the case of sloping ramps, the

substratum is backfilled and the heating cable

is laid on the reinforcement or rolled asphalt.

In suspended structures the substratum may

consist of finished slabs, prestressed concrete

or a suspended structure with poured concrete.

Steel beams or planks with a concrete surface

are also permissible.

A suspended structure is normally covered by an

asphalt layer to prevent water penetration.

The heating cable can be laid on any of these

surfaces. In the case of poured concrete, though,

it should be ensured that the surface is smooth

and all sharp objects are removed. Roadways on

a solid substratum do not require any additional

thermal insulation.

Appropriate preparations should be made for

installing the temperature and moisture sensor. If

using hot asphalt, a spacer ring or similar should

be used to protect the sensor and supply lead

from the high asphalt temperature, as otherwise

the electronic components may be destroyed.

The remaining space can then be filled once it

has cooled. Please note that to ensure long-term

stability, any exposure of the sensor and supply

lead to an exposure temperature of up to 80°C

must be kept as brief as possible. For further

details, please refer to the operating instructions

for the sensor.

nVent.com | 9

PRE-INSTALLATION CHECKS

First make sure that the area to be heated

complies with the data in the design instructions.

Establish where the junction boxes are to be

installed and check that the connection leads

are long enough. The length is 3 m. Thoroughly

clean the substratum before starting to install the

heating cables, as sharp objects can damage the

heating cable.

Test the heating cable with an multimeter before

installation. This involves measuring the ohmic

resistance of the conductor and the insulation

resistance of the flexible connection lead. The

conductor resistance is measured with an

multimeter . A deviation of up to 10% from the

nominal resistance is permissible. See table on

page 3.

Connection lead

Conductor

Multimeter

Braid

Measurement of cable circuit resistance

Insulation

resistance

tester

Connection lead

Braid

Conductor

Insulation resistance

The insulation resistance should be measured with 1000 Vdc (min. 500 Vdc) on EM-MI

The reading has to be >100 MOhm.

Record all the measured values on the Installation Test Record provided.

10 | nVent.com

LAYOUT CONSIDERATIONS

Area to be heated

Determine the exact area to be heated. Consider the following factors:

Lay the heating cable right

up to the run-off gutter.

Covered

area

Covered area

Trace close to the

outside of corners.

Also heat the surfaces on

which braking will occur, e.g.

before a barrier or a magnetic

card reader.

Also heat

the run-off

gutter.

Also heat the

covered area of the

entry, as incoming

vehicles can bring in

snow.

Heat at least one

metre into the

covered area.

Do not run the

heating cable over

expansion joints.

The MI heating cable must not be shortened or spliced.

nVent.com | 11

Layout Schemes

INCORRECT CORRECT

Trace in long runs in

preference to short

runs.

For curved ramps, always

trace around the arc of

the bend, not radially (this

ensures that spacing is

maintained).

Do not cross expansion joints. Use a separate

circuit on each side of the joint.

Expansion joint

12 | nVent.com

HEATING CABLE INSTALLATION

• Secure the spacers in place with the aid of

suitable nails or nuts and bolts. On a sand

asphalt substratum, hot asphalt or bitumen

can be used instead to fasten the spacers.

• The laying spacing for the metal strip should

be approximately 0.5 m.

Maintain the given

laying spacing.

Spacer (prestamped

metal strip)

± 0.5 m distances

between the metal strips

Connections (connection

lead to heating cable)

Maintain a minimum

distance of 50 mm

from obstructions.

• Refer to the layout drawing and choose a

starting-point which both cables will return to.

• Unroll the heating cable carefully, without

twisting or distorting it. Take care not to

damage the outer jacket.

Keep the roll flat (horizontal) as you unroll it.

nVent.com | 13

• Lay the heating cable in loops so that both

connection leads can be connected in the

same junction box.

• Keep to the given laying spacing.

• The standard laying spacing ranges from 165

to 275 mm, according to the specific power

requirement. A minimum laying spacing of

55 mm must be maintained. Take care that

heating cables do not touch one another,

overlap or cross over.

• The smallest bending radius is 35 mm (or 5.5

x the heating cable diameter). (The minimum

laying temperature is –5°C).

• A distance of not less than 50 mm must be

observed between two connection leads.

Crossovers with the rigid connection lead and

the MI heating cable should be covered over

with asphalt.

•

Check that the MI heating cable is

completely covered with asphalt. The flexible

connection lead and the crossover with the

flexible and the rigid connection lead must not

be covered with asphalt

(see drawing on page 6).

• If the two connection leads are not going to

be routed to a junction box straight away, they

must be protected from moisture penetration

and mechanical damage.

Using Spacers to Fasten the Heating Cable to the Substratum

Laying spacing as given

The tongues are

laid backwards

over the heating

cable, to fix the

heating cable in

place.

Tongues bent backwards

over the heating cable.

Spacer (prestamped

metal strip)

Heating cable

(heat strip)

Tongue

Spacer (prestamped

metal strip)

14 | nVent.com

Install Conduit (6)

Install conduit (supplied on site) to protect the

cold lead cable where it exits the asphalt. Install

adaptors on each end of the conduit to protect

the end of the cable from sharp edges. The MI

heating cable and the crossover with the rigid

connection should be covered with asphalt. The

flexible connection leads and the connections

must not come into contact with asphalt. Either

lay them in sand, or use a conduit (see drawing).

Install the conduit so that neither the flexible

connection lead nor the crossover between the

rigid and the flexible lead come into contact

with the asphalt. Fix the conduit in place in such

a way that it will not be displaced during the

asphalt pour.

Rigid metal

conduit

Wall

Crossover with

rigid / flexible

connection lead

and flexible

connection lead

Flexible

connection lead

Rigid connection leadMI heating cable

Connect the Cold Lead Cable (2)

Connect the cold ends to the control panel

or a junction box (according to the layout) as

indicated. For the PE connection, the braid at each

flexible cold end should be twisted and a yellow-

green heat-shrinkable sleeve pulled over it.

Complete the Layout

Repeat the above sequence for all the heating

cable circuits.

Installing the Temperature and Moisture

Sensor (4)

Install the temperature and moisture sensor in

accordance with the instructions supplied with

the unit. Ensure that it is supported at the correct

height. For sensors comprising a separate

housing and sensor, install only the housing at

this stage.

• The sensor should be placed mid-way

between heating cable runs.

LNPE

Heating

cable circuit

Junction box

nVent.com | 15

• The sensor lead should be routed under the

asphalt layer.

Sensor Asphalt

Heating

cable

Conduit

==

50505050

Sensor

Heating

cable

• The sensor lead should be protected by a

metal conduit (7).

• The sensor must be mounted vertically, even

on inclined surfaces.

16 | nVent.com

Check Heating Cable

• Visually check the heating cable for damage.

• Verify that the heating cable has been

fastened to the spacers.

• Verify that the laying spacing has been

maintained and that the heating cable has

been kept away from expansion joints, sharp

edges, etc.

• Verify that the heating cable has been

installed at the correct depth.

• Visually check the connection leads for

correct installation.

Do a Layout Sketch

Record the layout of each circuit, with particular

reference to the position of the connection leads.

Perform an Insulation Resistance Test

Carry out an insulation resistance test on

each circuit to detect any damage that may

have occurred during or after installation. With

1000Vdc (min. 500Vdc) the resistance reading

must be greater than 100 MΩ Record the value

for each circuit on the Installation Test Record.

CHECK THE INSTALLATION

Checks

Perform the following checks before

applying the asphalt:

• Check for signs of heating cable

damage.

• Check the spacing and below-surface depth of

the heating cable, if applicable.

Insulation Resistance Test

It is advisable to perform an insulation resistance

test on all the heating circuits immediately before

asphalt pouring to detect any damage which

may have occurred after installation. Record the

insulation resistance of each heating circuit on

the Installation Test Record.

Before commencing asphalt pouring, ask the

asphalt team to verify the insulation resistance

results, record the asphalt temperature and sign

the Installation Test Record.

Asphalt Practice

Although the EM-MI heating cables have been

designed specifically for this application, they

are not indestructible. The asphalt working

temperature must not exceed 250°C. Avoid

extreme mechanical stresses.

After the Pour

After completion of all asphalt work, perform an

insulation resistance test and record the values

on the Installation Test Record.

ASPHALT PRACTICE

nVent.com | 17

Supplementary Asphalt Work

Work such as drain installation and placement of

anchor bolts is often done after the initial asphalt

pour. Consult the drawing of the layout so that

damage to the heating cable can be avoided.

After all such work has been completed, perform

an insulation resistance test and record the

result on the Installation Test Record.

Purpose

The drain tracing system ensures that melt water

can drain away.

Note: the drain tracing circuit should be

controlled by the same control system as the

other heating circuits.

Tools

• 2500 Vdc insulation multimeter

(min. 500 Vdc)

Install Junction box (11)

Choose a position:

• close to the drain

• indoors if possible.

Install Connection Kit (12)

Terminate the 8BTV2-CT heating cable into the

junction box in accordance with the instructions

provided with the Connection Kit.

Lay out the Heating cable (13)

Protect the heating cable with conduit

between the junction box and the drain. Trace

the entire length of the drain to ensure that melt

water will always have a run-off path.

Install the End Seal (14)

Install the end seal following the instructions

provided with the End Seal kit.

Perform an Insulation Resistance Test

The insulation resistance test detects damage

to the heating cable such as cuts or punctures.

It should be carried out using a 2500 Vdc

instrument. Lower voltage instruments are

less sensitive and are not recommended. The

instrument should have a test voltage of not less

than 500 Vdc.

DRAIN TRACING SYSTEM WITH SELF-REGULATING HEATING CABLE

8BTV2-CT

18 | nVent.com

Proceed as follows:

• Connect one lead to the heat strip braid.

• Connect the other lead to both heat strip

conductors together.

• Apply voltage. The resistance reading must

be greater than 100 MΩ.

• If the insulation resistance is less than this,

the heat strip is damaged. Where possible,

locate the fault and rectify. Record the

insulation resistance value on the Installation

Test Record.

Braid

2500 Vdc Insulation resistance tester

Conductors

Finishing

Install a grid over the drain to ensure that the heat

strip is protected from damage.

Note: A 30 mA residual current device (RCD)

is specified for the drain tracing. Ensure that

there are no more than 60 m of heating cable

connected to each 30 mA RCD.

FINISHING

Complete Sensor

Complete the installation of the sensor (where

necessary).

Install panel (8)

Install the electrical panels according to the

manufacturer’s instructions.

Install Controls (9)

EN 60335-1:1994 clause 7.2.12 requires at least

one all-pole circuit breaker (mains disconnection)

with a minimum contact gap of 3 mm. Install

control units, thermostats and manual control

equipment in accordance with the manufacturers’

instructions.

Complete Wiring and System (10)

Follow VDE 0100 Part 520 A3 and applicable

local regulations.

nVent.com | 19

OPERATION

Initial Start-up

Electrical Requirements

Complete all electrical testing following

applicable local codes and practices. Inspect

all wiring for conformance to design drawings.

Check for correct rating on all protection devices.

Controller Checks

Check controller in accordance with the

instructions provided with the unit.

Insulation Resistance Test

Perform a final insulation resistance test to

ensure that the connection lead and supply cable

have not been damaged since installation.

General Operation and Maintenance

The EM-MI System has no moving parts and

therefore requires minimum maintenance.

Local maintenance codes and requirements for

electrical equipment should be complied with.

Circuit breakers should be checked periodically.

Residual current devices (rcd) should be tested

annually.

Periodically inspect the system controls.

Operate the controls to ensure that they function

correctly.

Max. ambient temperature for MI heating cable:

90°C. Installer must supply operator with a layout

drawing. The heating circuit must be isolated

from the electrical supply during maintenance

and repair activities.

TROUBLE SHOOTING GUIDE

Warning: De-energize all power circuits before installation or servicing.

Problem A : Circuit breaker trips

Probable causes Correction

Electrical fault at:

• connection lead

• damaged heating cable

Locate and rectify the fault and reset

or replace circuit breaker.

Circuit breaker undersized

Re-establish what the current loads are going to be and

install new protection (NB: if circuit breaker is replaced,

ensure it is compatible with the supply cable).

Defective circuit breaker Replace

20 | nVent.com

Problem B: residual current device trips

Probable causes Correction

Excessive moisture in junction box Dry out and check seal; replace if necessary. Perform

an insulation resistance test.

Earth fault at:

• connection

• damaged heating cable

Locate and rectify the fault and reset or replace rcd.

Leakage current too high:

power cable or heating cable too long

Correct problem and re-design.

Contactor bouncing Replace with higher quality contactor

Voltage spikes in power supply network Reset rcd. If condition persists, use clean power

supply.

Defective RCD Replace

Problem C: Ice/snow not melting

Probable causes Correction

Loss of supply current due to over-current or

residual current device operating.

Follow procedures outlined in A and B above.

Loss of supply cable continuity Locate and rectify fault.

Incorrect setting or operation of system

controls

Repair system controls or set system controls

correctly

Incorrect contactor sizing or damaged contactor Rectify

Problem D: Ice/snow begin to melt, but system turns off too soon

Probable causes Correction

Incorrect setting or operation of system

controls.

Repair system control unit or set system controls

correctly.

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Raychem EM-MI Installationsguide

Raychem EM-MI Installationsguide

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