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 1.2 1.3 1.4 Contents and purpose ........................................................................................................................... 101 Meaning of signal words ........................................................................................................................ 101 Additional documentation to be used.................................................................................
Table of contents 6 Thermo 90 S / Thermo 90 ST Function tests 6.1 6.2 General ................................................................................................................................................. 601 Settings ................................................................................................................................................. 601 6.2.1 Setting the CO2 content.............................................................................................
Thermo 90 S / Thermo 90 ST 9 Table of contents Repair 9.1 General .................................................................................................................................................. 901 9.1.1 Work on stripped-down components ........................................................................................... 901 9.2 Dismantling and assembling.................................................................................................................. 902 9.2.
List of illustrations Thermo 90 S / Thermo 90 ST List of illustrations 301 Sequence of functions ............................................................................................................................... 302 501 502 503 504 505 General fault indications ............................................................................................................................ Fault indications on fault lock-out .......................................................................
Thermo 90 S / Thermo 90 ST 1 Introduction 1 Introduction 1.4.1 General safety regulations 1.1 Contents and purpose The year of first start-up must be indelibly identified on the rating plate by removing the corresponding year number. 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.
1 Introduction 1.5 Statutory regulations governing installation Refer to the installation instructions for the statutory regulations if necessary. Thermo 90 S / Thermo 90 ST 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.
Thermo 90 S / Thermo 90 ST 2 2 General description General description 2 hours after the heater is switched on. The Thermo 90 S and Thermo 90 ST heater is principally composed of 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.
2 General description Thermo 90 S / Thermo 90 ST 4 3 2 1 5 6 11 8 9 1 2 3 4 5 6 7 8 9 10 11 7 10 Combustion air fan Fuel connection Temperature sensor Temperature limiter Heat exchanger Inlet, coolant Circulating pump Outlet, coolant Outlet, exhaust gas Inlet, combustion air 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.
Thermo 90 S / Thermo 90 ST 2.3 Temperature sensor 2.8 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 2 General description Combustion pipe The mixture of fuel and air burns in the combustion pipe, thus causing the heat exchanger to become hot.
2 General description Page for notes 204 Thermo 90 S / Thermo 90 ST
Thermo 90 S / Thermo 90 ST 3 Function description (Fig. 301) 3.1 Switching on 3 Function description The “operating indicator” on the digital timer lights up when the “immediate heating” button is pressed. or 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.
3 Function description 2 1 3 A 5 4 Thermo 90 S / Thermo 90 ST 7 6 12 8 9 10 11 15 13 14 18 16 17 22 19 20 21 23 * If no flame is formed, the start is automatically repeated (20 s pulse preglow, 90 s safety time). 1 0 1 /4 0 B 1 C 1 D 1 0 E 1 0 F 1 0 G 1 1 /2 1/4 0 * 0 30 80 90 75 70 °C ❏ o Possible regulating temperatures that can be set, see table below Safety time Fig. 301 Sequence of functions 3.
Thermo 90 S / Thermo 90 ST A B C D E F G 3.6 3 Function description Glow plug Metering pump Combustion air fan Flame monitor Operation indicator light Circulating pump Vehicle fan 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).
3 Function description 3.6.2 Diagnosis after fault lock-out Thermo 90 S and Thermo 90 ST Check the fuses and plug connectors. 3.6.2.
Thermo 90 S / Thermo 90 ST 3 Function description Page for notes 305
Thermo 90 S / Thermo 90 ST 4 4 Technical data Technical data 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. 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.
4 Technical data Page for notes 402 Thermo 90 S / Thermo 90 ST
Thermo 90 S / Thermo 90 ST 5 Troubleshooting 5.1 General This section describes how to identify and remedy faults on the Thermo 90 S und Thermo 90 ST heater. CAUTION Troubleshooting work demands precise knowledge of the structure and theory of operation of the various components and must be carried out by trained personnel only. If in doubt, refer to sections 2 and 3 for a description of how the functions interact.
5 Troubleshooting 5.3 Thermo 90 S / Thermo 90 ST Fault indications on fault lock-out NOTE If the system is operated with a switch, the nature of the fault is indicated by a flashing code on an indicator light during the run-on time of the heater. After five short signals, count the long flashes. In the Thermo 90 S heater with a standard clock, the fault is output on the clock display (see 3.6.3). The following table can be used accordingly.
Thermo 90 S / Thermo 90 ST 5 Troubleshooting Fault indication Possible cause Remedy 9 Flashing pulses (glow plug defective) Cabling Check cabling for damage, discontinuity and short-circuit Flow plug defective Replace glow plug 10 Flashing pulses (overheating) Heater overheats Check coolant and top up if necessary.
5 Troubleshooting Thermo 90 S / Thermo 90 ST 5.4.2 Back wall with metal evaporator 5.4.3 Combustion chamber • • The pilot flame outlet opening (Fig. 504) must be clear otherwise no start will occur. Remedy Replace burner • • Cracks, flaking as well as black or other discoloration of the evaporator do not lead to burner failure and are not significant. The combustion chamber (Fig. 505) should not be damaged (e.g. dented).
Thermo 90 S / Thermo 90 ST 6 Function tests 6 Function tests 6.3.3 Resistance test on the flame monitor 6.1 General If you conduct this electrical test with a digital multimeter, the flame monitor should have the following values: This section describes the tests conducted on the heater and its settings when it is installed and not installed to verify that it is in working order.
6 Function tests Page for notes 602 Thermo 90 S / Thermo 90 ST
Thermo 90 S / Thermo 90 ST 7 Circuit diagrams 7.1 General 7 Circuit diagrams The circuit diagrams (Figs. 701 to 704) show the possible circuits for the Thermo 90 S heater with – Standard clock – Standard clock and separate circulating pump control – ADR and switch – ADR and switch, without power take-off The circuit diagrams (Figs.
7 Circuit diagrams E B3 X1 B2 Thermo 90 S / Thermo 90 ST X1 1 2 3 X5 X3 4 5 X11 (ST 1) X6 X12 (ST 2) X13 (ST 3) 6 1 2 M1 M2 3 11 6 B1 12 11 10 9 8 9 7 1 12 9 2 2 11 7 5 1 3 58 15 9 2 7 5 1 3 1 1 58 15 30 30 F2 1 X6 F1 2 3 rt rt 2 F3 1 12 sw 3 8 ws 4 9 1 5 10 4 8 4 9 12 B4 7 2 3 11 7 5 6 10 2 2 1 rt 86 gn or or vi ge gr X13 (ST 3) ws/bl X11 (ST 1) X3 bl 7 6 br 11 12 8 A2 H6 sw H3 2 rt br H1 1 gn/ws rt/bl X
Thermo 90 S / Thermo 90 ST E B3 X1 B2 X1 1 2 3 7 Circuit diagrams X5 X3 4 5 X11 (ST 1) X6 X12 (ST 2) X13 (ST 3) 6 1 2 M1 M2 3 11 6 B1 12 11 10 9 8 9 7 1 12 11 9 2 2 7 1 5 3 58 15 9 2 7 5 1 3 1 1 58 15 30 30 F2 rt X12 (ST 2) 1 12 B4 7 5 2 X11 (ST 1) 2 3 11 7 6 10 2 1 X13 (ST 3) rt bl gn 87a 9 12 or 87 4 or 86 ge br X3 8 86 br 1 5 10 gr 9 4 K3 87 87a K5 85 30 85 sw 30 sw br S8 gn/ws rt/bl A2 11 7 6 4 vi/bl ws
7 Circuit diagrams E X1 B2 Thermo 90 S / Thermo 90 ST X5 X1 B3 1 2 3 4 5 X11 (ST 1) X6 X12 (ST 2) X13 (ST 3) 6 1 2 M1 M2 11 B1 8 1 7 2 2 9 11 7 1 5 3 9 2 7 1 5 3 F2 F3 58 15 D+/61 1 X6 S7 2 1 12 H2 B sw 3 E ws 4 1 8 6 B4 7 5 2 A2 11 9 1 5 10 8 4 9 12 2 3 11 7 6 10 2 1 rt 86 gn or or gr vi/bl vi bl rt br ge ws/bl X13 (ST 3) sw X11 (ST 1) br S4 F H5 Y2 87 30 sw br br 4 1 0 M E M2 M1 B3 B1 ϑ M A1 M3 S5
Thermo 90 S / Thermo 90 ST E X1 B2 7 Circuit diagrams X5 X1 B3 1 2 3 4 5 X11 (ST 1) X6 X12 (ST 2) X13 (ST 3) 6 1 2 M1 M2 11 B1 8 1 7 2 2 9 11 7 1 5 3 9 1 2 7 5 3 F2 F3 58 15 D+/61 1 X6 F1 2 1 12 F H2 B sw 3 E ws 4 11 8 B4 6 7 5 2 A2 9 1 5 10 8 4 9 12 2 3 11 7 6 10 2 1 rt 86 gn or or gr vi/bl vi bl rt br ge ws/bl X13 (ST 3) sw X11 (ST 1) br S4 1 gn/ws rt/bl X12 (ST 2) A 87 30 br sw M2 Item A1 A2 B1 B2 B3 B4 E F1 F2
7 Circuit diagrams Thermo 90 S / Thermo 90 ST ϑ 1 2 Temperature coding (temperature at water outlet): See table on page 302 Digital timer P2: with positive at connection 10 heating Connection 10 open programmed 3 Vehicle fuse 4 Vehicle fan switch Item A1 A2 B1 B2 B3 B4 E F1 F2 F3 H1 H3 H6 Designation Heater Control unit Flame monitor Temperature sensor Temperature limiter/ overheating guard circuit Cabin thermostat Glow plug 20 A fuse 5 A fuse 20 A fuse “Heating” symbol in the display Symbol light
Thermo 90 S / Thermo 90 ST 7 Circuit diagrams ϑ 1 Temperature coding (temperature at water outlet): See table on page 302 2 Digital timer P2: with positive at connection 10 heating Connection 10 open programmed 3 Vehicle fuse 4 Vehicle fan switch Item A1 A2 B1 B2 B3 Cable cross-sections < 7.5 m 0.75 mm 2 = Continuous operation with immediate 0.75 1.0 1.5 2.5 4.
7 Circuit diagrams Thermo 90 S / Thermo 90 ST ϑ 1 Temperature coding (temperature at water outlet): See table on page 302 ϑ 3 Vehicle fuse < 7.5 m 0.75 mm 2 4 Vehicle fan switch 0.75 1.0 1.5 2.5 4.0 Item A1 A2 B1 B2 B3 B4 E F1 F2 F3 H2 H5 K5 M1 M2 M3 S4 Designation Heater Control unit Flame monitor Temperature sensor Temperature limiter/ overheating guard circuit Cabin thermostat Glow plug 20 A fuse 5 A fuse 20 A fuse Light max. 2 W Lamp min. 1.
Thermo 90 S / Thermo 90 ST 7 Circuit diagrams ϑ 1 Temperature coding (temperature at water outlet): See table on page 302 ϑ Cable cross-sections 3 Vehicle fuse < 7.5 m 0.75 mm 2 7.5 - 15 m 4 Vehicle fan switch 0.75 1.0 1.5 2.5 4.
7 Circuit diagrams Page for notes 710 Thermo 90 S / Thermo 90 ST
Thermo 90 S / Thermo 90 ST 8 Service work 8.1 General 8 Service work This section describes the service work that can be carried out on the heater when it is installed. 8.2 Work on the heater Disconnect the main power cable from the vehicle’s battery before carrying out any work on the heater. The main battery power must not be disconnected whilst the heater is operating or running on as a result of the risk of the heater overheating and the overheating guard circuit thus being tripped.
8 Service work 8.4 Heater trial run The heater must not be operated in enclosed areas such as garages and workshops without an emissions extraction system, even if you use the timer. 8.5 Service work The following service work is to be carried out after or before each heating period to maintain the functional reliability of the heater: • Clean the exterior of the heater (avoid the ingress of water). • Check the electrical connections for contact corrosion and to ensure that they are secure.
Thermo 90 S / Thermo 90 ST 8 Service work NOTE The Thermo 90 S and Thermo 90 ST heater is supplied with the control unit mounted on the combustion air fan.
8 Service work 8.6 Visual inspections and installation instructions 8.6.1 Connection to the vehicle cooling system In thermostat circuits, only use thermostats which start to open at < 65 °C. The heater should be installed in as low a position as possible to allow the heater and circulating pump to be bled automatically. This is particularly important as the circulating pump is not self-priming. The heater is connected to the vehicle cooling system as shown in Fig. 801.
Thermo 90 S / Thermo 90 ST 8 Service work 8.6.2.1 Fuel extraction Vehicles with diesel engines The fuel must be taken from the vehicle fuel tank or from a separate tank (Figs. 803, 804 and 805). Fuel extractor Sealing ring 25 Hole pattern Tank fitting > 25 mm Only use a fuel extractor with metal fuel tanks Fig. 805 Fuel extraction from the plastic tank (extraction through tank fitting) Fig.
8 Service work Thermo 90 S / Thermo 90 ST The fuel extractor should not be located near the engine, as gas bubbles may form in the lines on account of heat radiated from the engine. This may cause problems during combustion. When installing the heater in a vehicle with fuel injection system, it is important to establish whether the fuel pump is located inside or outside the tank. If the fuel pump is located inside the tank, fuel can only be extracted from the return line.
Thermo 90 S / Thermo 90 ST 8 Service work 8.6.3 Metering pump with damper 8.6.3.2 Installation and attachment The metering pump is a combined delivery, metering and shut-off system and is subject to certain installation criteria (Figs. 802 and 808). The metering pump must be secured with a vibrationdamping mounting. Its installation position is limited as shown in Fig. 808 in order to ensure effective automatic bleeding. 8.6.4 Fuel filter Only a Webasto filter, order no.
8 Service work Thermo 90 S / Thermo 90 ST 8.6.6 Exhaust line The exhaust line (internal diameter 38 mm) can be installed with a length of 0.5 m to 5 m and several bends (360° altogether, minimum bending radius 85 mm). The exhaust muffler is essential and must be installed near the heater. An attachment is required no further than 150 mm from the end of the exhaust pipe to ensure that the angle of 90° ±10° is achieved.
Thermo 90 S / Thermo 90 ST 8 Service work 8.7.2 Changing the circulating pump 8.8 NOTE The process for changing the circulating pump is the same irrespective of whether the heater is installed or removed. Change as described in 9.2.2. After you have installed the heater, bleed the coolant circuit and the fuel supply system carefully. Comply with the instructions given by the vehicle manufacturer when doing this.
Thermo 90 S / Thermo 90 ST 9 Repair 9.1 General 9 Repair 9.1.1.1 Cleaning • Clean all stripped down components. 9.1.1.2 Visual inspection This section describes the repair work which is permitted on the heater when it has been removed. Any further dismantling will invalidate the warranty. Only use the spare parts from the appropriate spare parts kits for assembling the heater. 9.1.1 Work on stripped-down components • • • Check all components for damage (cracks, deformation, wear, etc.
9 Repair 9.2 Thermo 90 S / Thermo 90 ST Dismantling and assembling 9.2.1 Electrical connections (Thermo 90 S) 9.2.1.1 Disconnecting the electrical connections (plug connector X1) NOTE All electrical connections are grouped together in the plug. Before removing a component, first disconnect the corresponding electrical connections. In the Thermo 90 S heater with flange-mounted combustion air fan, disconnect plug X1 on the heater and plug connector X12 on the control unit.
Thermo 90 S / Thermo 90 ST 9 Repair 9.2.2 Changing the circulating pump 9.2.2.2 Installation 9.2.2.1 Removal 1. Apply acid-free grease (Vaseline) to the sealing ring (1, Fig. 902). 2. Place the circulating pump (2, Fig. 902) in the assembly position and attach with the clip (3) and screws (4). 3. Tighten the screws (4) to 3 Nm ±10%. 4. Connect the electrical connections (see 9.2.1.2). 5. Install the heater (see 8.7.1.2). 1. 2. 3. 4. 5. Remove the heater (see 8.7.1.1).
9 Repair Thermo 90 S / Thermo 90 ST 9.2.3 Changing the temperature limiter 9.2.4 Changing the temperature sensor 9.2.3.1 Removal 9.2.4.1 Removal NOTE The temperature limiter only has to be removed if it is being replaced with a new one. The function must be checked in the installed condition. 1. Remove the heater (see 8.7.1.1). 2. Disconnect the electrical connections (see 9.2.1.1). 1. Remove the heater (see 8.7.1.1). 2. Disconnect the electrical connections (see 9.2.1.1). 3.
Thermo 90 S / Thermo 90 ST 9 Repair NOTE A Thermo 90 ST heater is shown. In the Thermo 90 S heater, the control unit can also be arranged on the combustion air fan without having any effect on changing the temperature sensor. 1 1 2 3 4 5 6 Protective cap Clip Temperature limiter Heat exchanger Round sealing ring Temperature sensor 2 3 6 4 5 Fig.
9 Repair Thermo 90 S / Thermo 90 ST 9.2.5 Changing the combustion air fan 9.2.5.2 Fitting 9.2.5.1 Removal NOTE Insert the shaped seal (3, Fig. 904) correctly and grease it (e.g. with Vaseline). Take care not to squash it. 1. 2. 3. 4. Remove the heater (see 8.7.1.1). Disconnect the electrical connections (see 9.2.1.1). Remove the screws (2, Fig. 904). Pull the combustion air fan (1) off the burner head (4) and remove together with the shaped sealing ring (3). 1.
Thermo 90 S / Thermo 90 ST 9.2.6 Changing the burner, flame monitor and glow plug 9.2.6.1 Removal 1. 2. 3. 4. 5. 6. 7. 8. 9. Remove the heater (see 8.7.1.1). Remove the combustion air fan (see 9.2.5.1). Remove the screw (5, Fig. 905) and washer (4). Remove the nuts (10) and pull off the bar (8). Pull the grommets (11 and 12) out of the slots in the housing of the combustion pipe (3). Pull the grommet (13) and burner (1) out of the burner head and remove with the swirl orifice (2).
9 Repair Thermo 90 S / Thermo 90 ST NOTE A Thermo 90 ST heater is shown. The figure can also be used for the Thermo 90 S heater. 1 13 12 11 6 7 8 9 10 2 4 5 3 Fig.
Thermo 90 S / Thermo 90 ST 9 Repair 9.2.7 Changing the burner head 9.2.7.2 Installation 9.2.7.1 Removal NOTE The burner head and exhaust outlet port can also be aligned during installation in the vehicle. 1. Remove the heater (see 8.7.1.1). 2. Remove the combustion air fan (see 9.2.5.1). 3. Remove the burner, flame monitor and glow plug (see 9.2.6.1). 4. Remove the mounting screw of the V-clamping collar (2, Fig. 906) and pull off the clamping collar. 5.
9 Repair Thermo 90 S / Thermo 90 ST 9.2.8 Changing the heat exchanger 9.2.8.2 Installation 9.2.8.1 Removal 1. Clip the connector housing onto the heat exchanger and insert the plug into the connector housing. 2. Install the burner head (see 9.2.7.2). 3. Install the burner, flame monitor and glow plug (see 9.2.6.2). 4. Fit the combustion air fan (see 9.2.5.2). 5. Install the temperature sensor (see 9.2.4.2). 6. Install the temperature limiter (see 9.2.3.2). 7. Fit the circulating pump (see 9.2.2.2). 8.
Thermo 90 S / Thermo 90 ST 10 10 Packing / Storage / Shipment Packing / Storage and Shipment 10.1 General If the heater or its components are sent to Webasto Thermosysteme GmbH for testing or repair, it must be cleaned and packed in such a way that it is protected against damage during handling, transport and storage. CAUTION Fully drain a complete heater before sending it back. Make sure that no fuel or coolant can leak out during packing and/or shipment. Seal the coolant ports with dummy plugs.
10 Packing / Storage / Shipment Page for notes 1002 Thermo 90 S / Thermo 90 ST
