Webasto Thermo 90 ST, Thermo 90 ST-ADR, Thermo 90 S, Thermo 90 S-ADR User Manual

Water heaters

Workshop manual

Thermo 90 S Thermo 90 S-ADR

(Transport of hazardous goods)

Thermo 90 ST Thermo 90 ST-ADR

(Transport of hazardous goods)

08/2004

Thermo 90 S / Thermo 90 ST Table of contents

Table of contents

1 Introduction

1.1 Contents and purpose ........................................................................................................................... 101

1.2 Meaning of signal words ........................................................................................................................ 101

1.3 Additional documentation to be used..................................................................................................... 101

1.4 Safety instructions and regulations........................................................................................................ 101

1.4.1 General safety regulations........................................................................................................... 101

1.5 Statutory regulations governing installation ............................................................................................102

1.6 Suggestions for improvements and modifications ................................................................................. 102

2 General description

2.1 Combustion air fan................................................................................................................................. 202

2.2 Heat exchanger ..................................................................................................................................... 202

2.3 Temperature sensor .............................................................................................................................. 203

2.4 Temperature limiter................................................................................................................................ 203

2.5 Burner insert .......................................................................................................................................... 203

2.6 Glow plug............................................................................................................................................... 203

2.7 Flame monitor........................................................................................................................................ 203

2.8 Combustion pipe.................................................................................................................................... 203

2.9 Circulating pump.................................................................................................................................... 203

2.10 Control unit ............................................................................................................................................ 203

2.11 Metering pump....................................................................................................................................... 203

3 Function description

3.1 Switching on .......................................................................................................................................... 301

3.2 Heating mode ........................................................................................................................................ 301

3.3 Control mode ......................................................................................................................................... 301

3.4 Switching off .......................................................................................................................................... 302

3.5 Heater functions when installed in ADR vehicles .................................................................................. 302

3.6 Malfunctions........................................................................................................................................... 303

3.6.1 Fault lock-out ............................................................................................................................... 303

3.6.2 Diagnosis after fault lock-out, Thermo 90 S and Thermo 90 ST ................................................. 304

4 Technical data ................................................................................................................................................ 401

5 Troubleshooting

5.1 General .................................................................................................................................................. 501

5.2 General fault indications ........................................................................................................................ 501

5.3 Fault indications on fault lock-out .......................................................................................................... 502

5.4 Visual check for assessing the burner ................................................................................................... 503

5.4.1 Burner housing .............................................................................................................................503

5.4.2 Back wall with metal evaporator .................................................................................................. 504

5.4.3 Combustion chamber .................................................................................................................. 504

5.4.4 Complete burner.......................................................................................................................... 504

Table of contents Thermo 90 S / Thermo 90 ST

6 Function tests

6.1 General ................................................................................................................................................. 601

6.2 Settings................................................................................................................................................. 601

6.2.1 Setting the CO

6.3 Testing individual components.............................................................................................................. 601

6.3.1 Resistance test of the temperature sensor ................................................................................. 601

6.3.2 Resistance test of the glow plug................................................................................................. 601

6.3.3 Resistance test of the flame monitor .......................................................................................... 601

6.3.4 Testing the combustion air fan.................................................................................................... 601

7 Circuit diagrams

7.1 General ................................................................................................................................................. 701

8 Service work

8.1 General ................................................................................................................................................. 801

8.2 Work on the heater ............................................................................................................................... 801

8.3 Work on the vehicle .............................................................................................................................. 801

8.4 Heater trial run ...................................................................................................................................... 802

8.5 Service work ......................................................................................................................................... 802

8.6 Visual inspections and installation instructions ..................................................................................... 804

8.6.1 Connection to the vehicle cooling system................................................................................... 804

8.6.2 Connection to the vehicle fuel system ........................................................................................ 804

8.6.3 Metering pump with damper ....................................................................................................... 807

8.6.4 Fuel filter..................................................................................................................................... 807

8.6.5 Combustion air supply ................................................................................................................ 807

8.6.6 Exhaust line ................................................................................................................................ 808

content.............................................................................................................. 601

8.7 Removal and installation....................................................................................................................... 808

8.7.1 Heater, removal and installation ................................................................................................. 808

8.7.2 Changing the circulating pump ................................................................................................... 809

8.7.3 Changing the temperature limiter ............................................................................................... 809

8.7.4 Changing the temperature sensor .............................................................................................. 809

8.7.5 Changing the combustion air fan................................................................................................ 809

8.8 Start-up ................................................................................................................................................. 809

Thermo 90 S / Thermo 90 ST Table of contents

9Repair

9.1 General .................................................................................................................................................. 901

9.1.1 Work on stripped-down components ........................................................................................... 901

9.2 Dismantling and assembling.................................................................................................................. 902

9.2.1 Electrical connections (Thermo 90 S).......................................................................................... 902

9.2.2 Changing the circulating pump .................................................................................................... 903

9.2.3 Changing the temperature limiter ................................................................................................ 904

9.2.4 Changing the temperature sensor ............................................................................................... 904

9.2.5 Changing the combustion air fan................................................................................................. 906

9.2.6 Changing the burner, flame monitor and glow plug..................................................................... 907

9.2.7 Changing the burner head........................................................................................................... 909

9.2.8 Changing the heat exchanger ..................................................................................................... 910

10 Packing, storage and shipment

10.1 General ................................................................................................................................................ 1001

III

List of illustrations Thermo 90 S / Thermo 90 ST

List of illustrations

301 Sequence of functions ............................................................................................................................... 302

501 General fault indications ............................................................................................................................ 501

502 Fault indications on fault lock-out .............................................................................................................. 502

503 Visual check, burner back wall................................................................................................................... 503

504 Visual check, pilot flame outlet opening ..................................................................................................... 504

505 Visual check, complete burner................................................................................................................... 504

701 System circuit for Thermo 90 S, 12 and 24 V, with standard clock............................................................ 702

702 System circuit for Thermo 90 S, 12 and 24 V, with standard clock and separate

circulating pump control ............................................................................................................................. 703

703 System circuit for Thermo 90 S-ADR, 24 V, with switch ............................................................................ 704

704 System circuit for Thermo 90 S-ADR, 24 V, with switch without power take-off ........................................ 705

705 System circuit for Thermo 90 ST, 12 and 24 V, with standard digital timer ............................................... 706

706 System circuit for Thermo 90 ST, 12 and 24 V, with standard digital timer and separate

circulating pump control ............................................................................................................................. 707

707 System circuit for Thermo 90 ST-ADR, 24 V, with switch .......................................................................... 708

708 System circuit for Thermo 90 ST-ADR, 24 V, with switch without power take-off...................................... 709

801 Specimen installations for heater in a truck ............................................................................................... 803

802 Fuel supply................................................................................................................................................. 804

803 Webasto fuel extractor............................................................................................................................... 805

804 Fuel extraction from the plastic tank (extraction through tank drain screw)............................................... 805

805 Fuel extraction from the plastic tank (extraction through tank fitting)......................................................... 805

806 Webasto fuel extractor............................................................................................................................... 806

807 Pipe/hose connection................................................................................................................................. 806

808 Metering pump, installation position and attachment ................................................................................ 807

809 Exhaust pipe opening, installation position................................................................................................ 808

901 Electrical connections (Thermo 90 S) ........................................................................................................ 902

902 Changing the circulating pump .................................................................................................................. 903

903 Changing the temperature limiter and temperature sensor ....................................................................... 905

904 Changing the combustion air fan ............................................................................................................... 906

905 Changing the burner, flame monitor and glow plug ................................................................................... 908

906 Changing the burner head ......................................................................................................................... 909

Thermo 90 S / Thermo 90 ST 1Introduction

1Introduction

1.1 Contents and purpose

This workshop manual is designed to assist trained personnel with repairing both the petrol and the diesel versions of the Thermo 90 S und Thermo 90 ST water heaters.

The heater is only allowed to be operated with the intended fuel (diesel or also with heating oil EL) and only in the particular prescribed electrical connection type.

1.2 Meaning of signal words

Throughout this manual, the signal words WARNING, CAUTION and NOTE have the following meanings:

WARNING

This heading is used to highlight operating instructions or procedures which, if not or not correctly followed, may result in personal injury or fatal accidents.

CAUTION

This heading is used to highlight operating instructions or procedures which, if not or not correctly followed, may result in damage to the equipment or its components.

1.4.1 General safety regulations

The year of first start-up must be indelibly identified on the rating plate by removing the corresponding year number.

The heaters are only licensed for heating the motor vehicle engine and vehicle cabin, not however for heating the hazardous material transport space.

The heater is only allowed to be installed in motor vehicles or in independent heating systems with a minimum coolant volume of 6 litres.

The heater is not allowed to be installed in the driver’s cab or passenger compartment of vehicles. If the heater is nevertheless installed in such a place, the installation box must be tightly sealed against the vehicle interior. The installation box must have sufficient external ventilation to ensure that a maximum temperature of 40 °C is not exceeded in the box. Malfunctions may occur if the temperature exceeds this level.

WARNING The heater must not be operated in enclosed areas, such as garages or workshops without an exhaust emissions extraction system, not even using the timer or Telestart, because of the risk of asphyxiation and poisoning.

NOTE

This heading is used to direct your attention to a special feature deemed essential to highlight.

1.3 Additional documentation to be used

This workshop manual contains all necessary information and instructions for repairing Thermo 90 S and Thermo 90 ST water heaters. Normally, there is no need to use additional documentation. If required, the installation instructions, the vehiclespecific installation instructions and the operating instructions can be used as well.

1.4 Safety instructions and regulations

In principle, the general accident prevention regulations and current works safety instructions are applicable. The “General safety regulations” that go beyond the scope of the above regulations are stated below.

Any special safety regulations relevant to this instruction manual will be highlighted in the relevant sections or text passages of the procedures.

The heater must be switched off at filling stations and fuel tank farms because of the risk of explosion.

CAUTION Wherever inflammable vapours or dust may form (for example near fuel, coal, wood dust or cereal stores or the like), the heater must be switched off because of the risk of explosion.

A temperature of 85 °C (storage temperature) must not be exceeded in the vicinity of the control unit (for example when completing painting work on the vehicle). If this temperature is exceeded, the electronic systems may suffer permanent damage.

Follow the instructions supplied by the vehicle manufacturer to check the cooling water level. The water in the heating circuit of the heater must contain at least 10% branded anti-freeze.

Non-compliance with the installation instructions and the warnings contained therein will lead to the exclusion of all liability by Webasto. The same applies if repairs are carried out incorrectly or with the use of parts other than genuine spare parts. This will result in the revocation of the type licence for the heater and therefore the general operating licence for the vehicle.

101

1Introduction Thermo 90 S / Thermo 90 ST

1.5 Statutory regulations governing installation

Refer to the installation instructions for the statutory regulations if necessary.

1.6 Suggestions for improvements and modifications

Complaints, improvement suggestions or corrections relating to this technical manual should be addressed to:

Webasto Thermosysteme International GmbH Technical Documentation Dept. D-82131 Stockdorf Tel.: +49 (89) 8579 4542 Fax: +49 (89) 8579 4757

102

Thermo 90 S / Thermo 90 ST 2 General description

2 General description

Thermo 90 S and Thermo 90 ST water heaters operate in conjunction with the vehicle’s own heating system and serve

– to heat the cab, – to defrost the vehicle windows and – to preheat water-cooled engines.

The water heater operates independently of the engine and is connected to the cooling system, the fuel system and the electrical system of the vehicle.

The concept of the heater is based on the evaporator principle. It is controlled by the temperature sensor and operates intermittently.

Depending on the deviation between the current coolant temperature and the nominal value measured at the temperature sensor, the burner power is regulated between the limits of 1.8 to 7.6 kW in diesel heaters and

1.8 to 7.6 kW in petrol heaters. When the heating requirement is particularly high (preheating), diesel heaters provide a maximum power of 9.1 kW for up to

2 hours after the heater is switched on. The Thermo 90 S and Thermo 90 ST heater is principally composed of

– the combustion air fan – the heat exchanger – the burner insert with combustion pipe – the circulating pump

To control and monitor it, the heater has

– a control unit (external) – a flame monitor – a glow plug – a temperature sensor – a temperature limiter

inside it.

In the case of the Thermo 90 S heater, the control unit can also be flange-mounted on the combustion air fan.

The Thermo 90 ST heater is delivered with the control unit already flange-mounted on the combustion air fan.

Thermo 90 S

10 Inlet, combustion air 11 Control unit (can also be

1 Combustion air fan 2 Fuel connection 3 Temperature sensor 4 Temperature limiter 5 Heat exchanger 6 Inlet, coolant 7 Circulating pump 8 Outlet, coolant

9 Outlet, exhaust gas

arranged externally in the vehicle)

Thermo 90 S heater

201

2 General description Thermo 90 S / Thermo 90 ST

1 Combustion air fan 2 Fuel connection 3 Temperature sensor 4 Temperature limiter 5 Heat exchanger 6 Inlet, coolant 7 Circulating pump 8 Outlet, coolant

9 Outlet, exhaust gas 10 Inlet, combustion air 11 Control unit

Thermo 90 ST heater

2.1 Combustion air fan

The combustion air fan supplies the air required for the combustion process from the combustion air inlet to the burner insert.

2.2 Heat exchanger

In the heat exchanger, the heat generated by combustion is transferred to the coolant circuit.

Temperature limiter

Temperature sensor

202

Combustion air fan

Heat exchanger

Thermo 90 S / Thermo 90 ST 2 General description

2.3 Temperature sensor

The temperature sensor records the coolant temperature at the coolant outlet of the heater as an electrical resistance. This signal is fed to the control unit where it is processed.

2.4 Temperature limiter

The overheating guard circuit (bimetallic) protects the heater against impermissibly high operating temperatures. The overheating guard circuit trips if the heat exchanger temperature exceeds 127 ±7 °C and switches off the heater.

2.5 Burner insert

The fuel is distributed over the burner cross-section in the combustion pipe in the burner insert.

2.6 Glow plug

The mixture of fuel and air is ignited by the glow plug when the heater is started. The glow plug takes the form of an electrical resistor and is positioned in the burner insert on the side away from the flame.

2.8 Combustion pipe

The mixture of fuel and air burns in the combustion pipe, thus causing the heat exchanger to become hot.

Combustion pipe

2.9 Circulating pump

The circulating pump ensures that coolant is pumped through the vehicle and heater circuits. The pump is switched on by the control unit and it runs throughout operation of the heater (including in the control pause).

Burner insert

Glow plug

Flame monitor

2.7 Flame monitor

The flame monitor is a low-ohm PTC resistor, which changes its resistance depending on the heat emitted by the flame. The signals are fed to the control unit where they are processed. The flame status is monitored by the flame monitor whenever the heater is operating.

Circulating pump

2.10 Control unit

The control unit is the central component. It guarantees the sequence of functions and monitoring of combustion mode. It is flange-mounted on the combustion air fan, although in the case of the Thermo 90 S it may be installed externally in the vehicle.

2.11 Metering pump

The fuel supply and metering for the heater is assured by an external metering pump. It addition, it serves as a shutoff element when the heater is switched off. The solenoid coil of the metering pump receives its pulses from the microprocessor in the control unit.

203

2 General description Thermo 90 S / Thermo 90 ST

Page for notes

204

Thermo 90 S / Thermo 90 ST 3 Function description

3 Function description

(Fig. 301)

3.1 Switching on

The “operating indicator” on the digital timer lights up when the “immediate heating” button is pressed.

When switching on with the switch, the operating indicator in the switch lights up.

The circulating pump, glow plug and combustion air fan start operating.

3.2 Heating mode

Combustion starts after approx. 60 to 140 seconds. Automatically controlled heating operation runs at full load for a maximum of 2 hours.

The vehicle’s own heater fan does not switch on until the heat carrier (coolant) has heated up sufficiently. Once the preset nominal temperature has been reached (see table of regulating temperatures) the heating power is reduced to the lowest part load in small individual steps.

3.3 Control mode

The heater switches to the control pause if the temperature of the coolant continues to rise to the threshold of the control pause. The circulating pump, the vehicle’s own heater fan and the operating indicator continue to operate during the control pause. The heater restarts when the coolant cools to the preset temperature for switching back on.

Diesel heaters

If the water temperature in the heater is higher than the nominal temperature but has not yet reached the threshold for the control pause and if the temperature then falls back to the nominal temperature within 10 minutes (after reaching this temperature for the first time), the heater switches back to the 9.0 kW heating stage. When the nominal temperature is reached, the heater is only switched back on again up to the 7.6 kW heating stage.

Petrol heaters

The maximum heating power in petrol heaters is always 7.6 kW.

301

3 Function description Thermo 90 S / Thermo 90 ST

2 5 7

1 0

Safety time

181512

986431

30 80 90 75 70 °C

212019171614131110

Fig. 301 Sequence of functions

* If no flame is formed, the

start is automatically repeated (20 s pulse preglow, 90 s safety time).

o Possible regulating

❏

temperatures that can be set, see table below

3.4 Switching off

The operating indicator on the digital timer/switch goes out when the heater is switched off. The combustion process will be ended and the run-on phase will start. The circulating pump and the combustion air fan continue to run, however, in order to cool down the heater (run-on) and are switched off automatically after approx. 105 seconds. The heater may be switched on again during the run-on time.

The temperature in the cabin can also be controlled using the vehicle’s own heater fan with a cabin thermostat.

3.5 Heater functions when installed in ADR vehicles

Sequence of functions for Thermo 90 S and ST

Switch on

Component interrogation

Pre-glow 40 s (pulsed)

Metering pump supply 5 – 7 s (1)

Metering pump / part load (1/4)

Flame monitor take-over

Stabilisation time

Full load

Vehicle fan “On”

Control range

Control pause

Flame monitor “Cold” (0)

The heater is started using the switch. An ADR case (constrained shut-off) is triggered when

– the vehicle’s engine is switched off, – a pumping device is started,

in which case the short run-on is terminated after 20 seconds (Thermo 90 S) and after 40 seconds (Thermo 90 ST).

Following this, the control unit is left in the “fault lock-out” status. The on/off switch must be moved to “Off” before it can be restarted.

The disconnecting switch (emergency off switch) is only allowed to be used in case of danger, because the heater is switched off without any run-on (overheating possible).

Run-on ended

Pre-glow 15 – 20 s (pulsed)

Metering pump supply 5 – 7 s (1)

Metering pump / part load (1/4)

Flame monitor take-over

Stabilisation time

Coolant temperature reduced

Full load

Switch off (run-on)

Flame monitor “Cold” (0)

Run-on ended

302

Thermo 90 S / Thermo 90 ST 3 Function description

A Glow plug B Metering pump C Combustion air fan D Flame monitor E Operation indicator light F Circulating pump G Vehicle fan

3.6 Malfunctions

3.6.1 Fault lock-out

Fuel is supplied for max. 240 seconds if the flame does not start to burn.

Fuel is supplied for max. 240 seconds if the flame goes out during operation.

The fuel supply is shut off if the system overheats (temperature limiter is tripped). If the system overheats, the button on the temperature limiter must be reset.

Once the cause of the fault has been eliminated, the fault lock-out is cancelled by switching the heater off and on again.

If the undervoltage guard switches off the system

Thermo 90 S and Thermo 90 ST

12 volts 10.5 V - 0.5 V

24 volts 21 V -1 V

for longer than 20 seconds, the fuel supply is interrupted.

CAUTION

A forced reset of the return spring when hot can result in damage to the component.

303

3 Function description Thermo 90 S / Thermo 90 ST

3.6.2 Diagnosis after fault lock-out Thermo 90 S and Thermo 90 ST

Check the fuses and plug connectors.

3.6.2.1 Version with digital timer

If the system is equipped with a standard clock, a fault message appears on the display of the digital timer after a fault occurs:

F 01 No start (after 2 attempts to start) F 02 Flame failure F 03 Undervoltage or overvoltage F 04 Premature flame recognition F 05 Flame monitor interrupt or flame monitor short

circuit

F 06 Temperature sensor interrupt or temperature

sensor short circuit

F 07 Metering pump interrupt or metering pump short

circuit

F 08 Fan motor interrupt or fan motor short circuit or

fan motor incorrect speed F 09 Glow plug interrupt or glow plug short circuit F10 Overheating F 11 Circulating pump interrupt or circulating pump

short circuit

3.6.2.2 Version with switch

If the system is operated with a switch, the nature of the fault is indicated by a flashing code indicator light during the run-on time of the heater.

After five short signals, count the long flashes:

1x No start (after 2 attempts to start) 2x Flame failure 3x Undervoltage or overvoltage 4x Premature flame recognition 5x Flame monitor interrupt or flame monitor short

circuit

6x Temperature sensor interrupt or temperature

sensor short circuit

7x Metering pump interrupt or metering pump short

circuit

8x Fan motor interrupt or fan motor short circuit or fan

motor incorrect speed 9x Glow plug interrupt or glow plug short circuit 10x Overheating 11x Circulating pump interrupt or circulating pump short

circuit

on an operating

304

Thermo 90 S / Thermo 90 ST 3 Function description

Page for notes

305

Thermo 90 S / Thermo 90 ST 4 Technical data

4 Technical data

Except where limit values are specified, the technical data below refer to the usual heater tolerances of ±10% at an ambient temperature of +20 °C and at the rated voltage.

Fuel for Thermo 90 S / Thermo 90 ST and Thermo 90 S-ADR / Thermo 90 ST-ADR (diesel):

The diesel fuel specified by the manufacturer must be used.

Electrical components

The control unit, motors for combustion air fan and circulating pump, glow plug, switch and digital timer (no timer for ADR mode) are designed for either 12 volts or 24 volts. The temperature limiter, temperature sensor and flame

We know of no negative influences due to additives. If fuel is extracted from the vehicle’s tank, follow the additive instructions issued by the vehicle manufacturer. If you change to low-temperature fuel, the heater must be operated for approx. 15 minutes so that the fuel line and fuel pump are filled with the new fuel.

monitor are identical on 12 V and 24 V heaters.

Fuel for Thermo 90 S / Thermo 90 ST petrol:

The fuel specified by the manufacturer must be used. Both leaded and unleaded fuel may be used.

Heater Operation Thermo 90 S

Petrol

EC licensing symbol ~S299 ~S298

Model Water heater with Ferro-Tec technology

Heat output Max.

regulating range

Fuel Petrol Diesel

Fuel consumption Max.

Rated voltage 12 volts 12 or 24 volts

Operating voltage range 10 ... 15 volts 10 ... 15 or 20 ... 30 volts

Nominal power consumption with circulating pump (without vehicle fan)

Max. ambient temperature: Heater: - Operation -40 ... +110 °C (90 °C with control unit installed on heater)

- Storage -40 ... +110 °C (90 °C with control unit installed on heater)

Control unit: - Operation -40 ... +75 °C -40 ... +85 °C -40 ... +75 °C -40 ... +85 °C

- Storage -40 ... +85 °C

Metering pump: - Operation -40 ... +20 °C -40 ... +40 °C

- Storage -40 ... +85 °C

Permitted operating pressure (heat carrier) Max. 2.0 bar

Capacity of the heat exchanger 0.15 l

Max. combustion air intake temperature +40 °C

Minimum capacity of the circuit 6.00 l

Delivery rate of the circulating pump against 0.15 bar

in exhaust fumes (permitted function

range)

adjustment values at approx. +20 °C

and geographic altitude above sea level

Heater dimensions (tolerance ± 3 mm) * Control unit installed on the heater

Weight 4.8 kg

regulating range

Max. regulating range

Max. 10 ... 12.0% by volume

Max. 0 m 500 m 1000 m

L 310 (355*) mm

2.0 kW – 7.6 kW

0.25 l/h – 1.0 l/h

37 W – 83 W

W 131 mm

H 232 mm

Thermo 90 ST

Petrol

10% 10.6% 11.3%

L 307 (352*) mm

W 131 mm

H 232 mm

Thermo 90 S diesel

Thermo 90 S-ADR

1.8 kW – 7.6 kW

0.19 l/h – 0.9 l/h

1650 l/h

L 310 (355*) mm

W 131 mm

H 232 mm

Thermo 90 ST diesel

Thermo 90 ST-ADR

9.1 kW

1.1 l/h

90 W

37 W – 83 W

L 307 (352*) mm

W 131 mm

H 232 mm

401

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