Water Heaters Workshop Manual Thermo 90 Thermo 90-TRS (Transport of hazardous goods) Thermo 90 S Thermo 90 S-TRS (Transport of hazardous goods) Type BW 80 (Fuel) Type DW 80 (Diesel) 09/2001
Thermo 90 List of Contents List of Contents 1 Introduction 1.1 1.2 1.3 1.4 Scope and Purpose ............................................................................................................................... 101 Meaning of Warnings, Cautions, and Notes .......................................................................................... 101 Additional Documentation to be used ....................................................................................................
List of Contents 6 Thermo 90 Functional Tests 6.1 6.2 General ................................................................................................................................................. 601 Adjustments .......................................................................................................................................... 601 6.2.1 Adjustment of the CO2 Contents ................................................................................................ 601 6.
Thermo 90 9 List of Contents Repair 9.1 General .................................................................................................................................................. 901 9.1.1 Work on Components after Disassembly .................................................................................... 901 9.2 Disassembly and Assembly................................................................................................................... 902 9.2.1 9.2.2 9.2.3 9.2.4 9.2.
List of Figures Thermo 90 List of Figures 301 Functional Sequence ................................................................................................................................. 302 501 502 503 504 505 General Failure Symptoms ........................................................................................................................ Failure Symptoms after Switch-off upon Failure ........................................................................................
Thermo 90 1 Introduction 1.1 Scope and Purpose This repair shop manual is intended to support familiarised personnel in the repair of Thermo 90 and Thermo 90 S for the Diesel and fuel type. The water heater may only be operated with the specified fuel (diesel or also fuel oil EL) and the relevant designated type of electrical connection. 1 Introduction 1.
1 Introduction For the installation of the Thermo 90-TRS or Thermo 90 S-TRS in vehicles used for the transportation of dangerous goods, in addition to the StVZO, the requirements in TRS 002 and TRS 003 (Technical Guidelines for the Transportation of Dangerous Goods on Roads) must be met. The heater may only be installed in motor vehicles or in independent heating systems with a minimum coolant capacity of 6 litres. The heater must not be installed in the passenger or driver compartments of vehicles.
Thermo 90 • Installation Instructions for Webasto fuel tanks for the fuel supply of water heaters in vehicles: In busses the installation is not permitted in the passengers or driver's compartment. • The fuel filler neck must not be located in the passengers or driver's compartment of any vehicle. • Fuel containers for carburettor fuel must not be located immediately behind the front panelling of the vehicle.
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Thermo 90 2 2 General Description General Description The water heater Thermo 90 and Thermo 90 S basically consists of: The water heater Webasto Thermo 90 and Thermo 90 S in combination with the vehicle's own heating system is used to: – – – heat the cabin defrost the windshields preheat water-cooled engines.
2 General Description Thermo 90 4 0S 9 mo er 3 Th 2 5 1 6 11 7 10 8 9 1 2 3 4 5 6 7 8 9 10 11 Combustion Air Fan Fuel Connection Temperature Sensor Temperature Limiter Heat Exchanger Inlet, Coolant Circulation Pump Outlet, Coolant Outlet, Exhaust Inlet, Combustion Air Control unit (may also be located externally in the vehicle) Heater Thermo 90 S 2.1 Combustion Air Fan The combustion air fan delivers the air required for combustion from the combustion air inlet to the burner insert. 2.
Thermo 90 2.3 2 General Description Temperature Sensor 2.8 The temperature sensor senses the coolant temperature in the heat exchanger of the heater unit as electrical resistance. This signal is fed to the control unit for processing. 2.4 Combustion Tube Inside the combustion tube the combustion of the fuel/air mixture takes place, heating up the heat exchanger. Temperature Limiter The overheat protection (bimetal) protects the heater unit from excessive operating temperatures.
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Thermo 90 3 Functional Description (Fig. 301) 3.1 Switch-on 3 Functional Description When operating the push button "Immediate Heating", the "Operating Indicator" on the timer illuminates or by activation with the switch, the operating indicator integrated in the switch illuminates. Circulation pump, glow plug, and combustion air fan are put into operation. 3.2 Heating Operation After approx.
3 Functional Description 2 1 3 A 5 4 Thermo 90 7 6 12 8 9 10 11 15 13 14 18 16 17 22 19 20 21 23 * In case of a no-flamecondition automatic restart is initiated (20 sec. cycled preheating, 90 sec. safety time) 1 0 1 / 0 B 1 4 C 1 2 D 1 0 E 1 0 F 1 0 G 1 1 / 1/4 0 * 0 30 80 90 75 70 °C ❏ o Possible codeable control temperatures, see table below Sicherheitszeit 3.
Thermo 90 3 Functional Description G Vehicle Blower Setting of Control Temperatures Thermo 90 Table Minus to B6 B6 not used Plus to B6 In case of overheating, the knob of the temperature limiter has to be reset after the unit has cooled down. Rated Temp. at Sensor Control Idle Reactivation after Control Idle 80° C 72° C 65° C 90° C 82° C 75° C 75° C 67° C 60° C On the standard wiring harness B6 is not in use.
3 Functional Description 3.6.
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Thermo 90 4 4 Technical Data Technical Data As long as no threshold values are given, the following technical data are understood to include tolerances of ±10% usual for heaters at an ambient temperature of +20° C and at nominal voltage and conditions. Electrical Components: Control unit, combustion air fan motor and dosing pump, glow plug, control switch and timer are either of the 12 V or 24 V type.
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Thermo 90 5 Troubleshooting 5 Troubleshooting 5.1 General This section describes troubleshooting procedures for the Water Heater Thermo 90 and Thermo 90 S. CAUTION Troubleshooting requires profound knowledge about structure and theory of operation of heater components and may only be performed by skilled personnel. In cases of doubt refer to Sections 2 or 3 for functional interrelations. CAUTION Troubleshooting is normally limited to the isolation of defective components.
5 Troubleshooting 5.3 Thermo 90 Failure Symptoms after Switch-off upon Failure NOTE When operated with a switch the type of failure is indicated by a flash code of the operation indicator light during heater run-down. The heater Thermo 90 S with standard timer outputs errors to the timer display for indication (see 3.6.3). The following table may also be used as representative reference. After five short signals the long flash pulses are counted.
Thermo 90 5 Troubleshooting Failure Symptom Failure Symptom Remedy 8 Flash pulses (combustion air fan defective) Wiring Check wiring for damage, open connections or short circuit Combustion air fan defective Replace combustion air fan Wiring Check wiring for damage, open connections or short circuit Glow plug defective Replace glow plug 9 Flash pulses (glow plug defective) Fig. 502 Failure Symptoms after Switch-off upon Failure (Sheet 2 of 2) 5.
5 Troubleshooting Thermo 90 5.4.2 Rear Wall with Metal Evaporator 5.4.3 Combustion Chamber • • The pilot flame exit bore (Fig. 504) must not be clogged, otherwise there will be no start. Remedy Replace burner • • Cracks, delaminations, as well as black or other discolorations of the evaporator do not cause a burner failure and are meaningless. The combustion chamber (Fig. 505) should not be damaged (e.g. dented).
Thermo 90 6 Functional Tests 6 Functional Tests 6.3.3 Flame Sensor Resistance Test 6.1 General During electrical testing of the flame sensor using a digital multimeter, the following readings should be obtained: This section describes the on-vehicle and off-vehicle testing of the heater to check its proper operation. WARNING The heater shall not be operated in enclosed areas like garages or workshops not provided with exhaust venting facilities. Cold test: Resistance at 25° C: 2.6 ... 3.
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Thermo 90 7 Circuit Diagrams 7 Circuit Diagrams 7.1 General The circuit diagrams (Figs. 702 and 703) show possible circuits of the heater Thermo 90 with – 3-times-clock – TRS equipment The circuit diagrams (Figs. 704 through 706) show possible circuits of the heater Thermo 90 S with – standard timer – TRS equipment – TRS equipment without auxiliary drive Fig. 701 shows the pin assignment (X1) for Thermo 90 and Thermo 90 S.
7 Circuit Diagrams Thermo 90 ϑ 1 For fuel heaters remove this connection 2 Temperature coding (temperature at water outlet): see table page 302 3 Item A1 A2 B1 B2 B3 B4 E F1 F2 F3 H1 H3 H4 K1 K2 K5 K6 Wire gauges Timer P: with plus at connection 4 = permanent operation in immediate heating without plus at connection 4 = heating period 1 hour Nomenclature Heater Control Unit Flame Sensor Temperature Sensor Temperature Limiter Room Thermostat Glow Plug Fuse 20 A Fuse 5 A Fuse 20 A Symbol for “Heati
Thermo 90 7 Circuit Diagrams ϑ 1 For fuel heaters remove this connection 2 Temperature coding (temperature at water outlet): see table page 302 3 Item A1 A2 B1 B2 B3 B4 E F1 F2 F3 H2 H4 K1 K2 K5 M1 M2 M3 Remark Thermo 90 SG 1569 Flat Fuse SAE J 1284 Flat Fuse SAE J 1284 Flat Fuse SAE J 1284 Operation indication (max. 2 W) max.
7 Circuit Diagrams Thermo 90 ϑ 2 4 Temperature coding (temperature at water outlet): see table page 302 Timer P2: with plus at connection 10 without plus at connection 10 Wire gauges = permanent operation in instant heating = heating period programmable = (10 min to 120 min); = basic setting 120 min Item A1 A2 B1 B2 B3 B4 E F1 F2 F3 H1 Nomenclature Heater Control Unit Flame Sensor Temperature Sensor Temperature Limiter Room Thermostat Glow Plug Fuse 20 A Fuse 5 A Fuse 20 A Symbol for “Heating” in Di
Thermo 90 7 Circuit Diagrams ϑ 2 Item A1 A2 B1 B2 B3 B4 E F1 F2 F3 H2 H5 K5 M1 M2 M3 S4 S5 Temperature coding (temperature at water outlet): see table page 302 Nomenclature Heater Control Unit Flame Sensor Temperature Sensor Temperature Limiter Room Thermostat Glow Plug Fuse 20 A Fuse 5 A Fuse 20 A Light in item S4 Lamp, at least 1.
7 Circuit Diagrams Thermo 90 ϑ 2 Item A1 A2 B1 B2 B3 B4 E F1 F2 F3 H2 K5 M1 M2 M3 S4 S5 Temperature coding (temperature at water outlet): see table page 302 Nomenclature Heater Control Unit Flame Sensor Temperature Sensor Temperature Limiter Room Thermostat Glow Plug Fuse 20 A Fuse 5 A Fuse 20 A Light in item S4 Relay Motor Motor Motor Switch Isolation Switch 1-pole or 2-pole Remark Thermo 90 / Thermo 90 S ϑ Wire gauges Item X1 X5 X6 X11 X12 X13 Y1 < 7.5 m 7.5 - 15 m 0.75 mm2 1.0 mm2 1.5 mm2 2.
Thermo 90 8 Servicing 8.1 General 8 Servicing This section describes the servicing procedures that may be performed with the heater installed. 8.2 Work on the Heater Prior to performing any work, it is mandatory to disconnect the vehicle battery main lead. As long as the heater is in operation or in run-down, the battery main supply must not be disconnected due to the danger of overheating resulting in a response of the overheat protection.
8 Servicing 8.4 Heater Test Run WARNING The heater must not be operated, not even with timer, in enclosed areas like garages or workshops not equipped with an exhaust venting facility. 8.5 Servicing Before or after each heating season the following servicing should be performed to maintain the heater's functional reliability: • Clean heater exterior (prevent the ingress of water). • Examine electrical connections for corrosion of contacts and for security.
Thermo 90 8 Servicing NOTE Manufacturer mounts control unit of heaters Thermo 90 S to combustion air fan.
8 Servicing Thermo 90 Fig. 801 Example for Heater Installation in Lorry 8.6 Visual Inspections and Installation Regulations 8.6.1 Connection to the Vehicle's Cooling System In thermostat circuits only thermostats opening at < 65° C are to be used. The installation of the heater should be in a location as low as possible to ensure self-venting of the heater and circulation pump. This applies in particular for the circulation pump, which is not self-sucking.
Thermo 90 8 Servicing 8.6.2.1 Fuel Tapping Fuel tapping must be from the fuel reservoir or from a separate tank (Figs. 803, 804, and 805). This separate fuel tapping avoids an influence on the pressure. Hole Pattern Fuel Tank Tap Gasket 25 > 25 mm Tank Fitting Plate Fig. 805 Fuel Tapping from Plastic Tank (tapping via fitting plate) Fig. 803 Webasto Fuel Tank Tap * Use fuel tank tap only on metal fuel tanks NOTE The fitting plate must be made of sheet metal.
8 Servicing Thermo 90 The fuel tap should not be located in the engine compartment because the radiation of engine heat may cause gas bubbles to build up in the fuel lines causing malfunctions in the combustion operation. Connection of 2 Pipes with Hose The proper connection of fuel lines with hoses is shown in Fig. 806. When installing the heater in vehicles with fuel injection system the fuel pump's location within or outside the fuel tank must be investigated first.
Thermo 90 8.6.3.1 Installation Location It is advantageous to mount the dosing pump in a cool location as near as possible to the tank. The ambient temperature must never exceed +20° C for fuel and +40° C for Diesel operated installations at any time while in operation. The maximum pressure at the tapping location must be below 1.5 bar. Dosing pump and fuel lines must not be installed in locations exposed to heat radiated by hot vehicle components. A heat shield is to be provided as required. 8.6.3.
8 Servicing 8.7 Removal and Installation Thermo 90 8.7.2 Replacement of Circulation Pump CAUTION In installed condition, only the following removal and disassembly procedures are allowed as long as the top cover is accessible for removal and sufficient space for removal is available: NOTE The procedure for replacement of the circulation pump is identical with the heater removed or installed. Replacement is to be performed in accordance with 9.2.2. – – – – – 8.7.
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Thermo 90 9 Repair 9.1 General 9 Repair 9.1.1.1 Cleaning • All disassembled components must be cleaned. 9.1.1.2 Visual Inspection This section describes the repairs that may be performed on the heater Thermo 90 when removed. Any further disassembly will void the warranty. For re-assembly only Webasto-authorised spare parts kits are to be used. 9.1.1 Work on Components afterDisassembly • • • Examine all components for damages (cracks, deformation, wear, etc.) and replace as necessary.
9 Repair 9.2 Thermo 90 Disassembly and Assembly 9.2.1 Electrical Connections (Fig. 901) 9.2.1.1 Disconnecting Electrical Connections (Connection X1) NOTE All electrical connections are joined in the connector. Prior to removal of a component, the relevant electrical connections first have to be disconnected. On heater Thermo 90 S with flanged combustion air fan connector X1 on heater and connection X12 on control unit must be disconnected and reconnected after making electrical connections.
Thermo 90 9 Repair 9.2.2 Replacement of Circulation Pump 9.2.2.2 Installation 9.2.2.1 Removal 1. Apply acid free grease (Vaseline) to gasket (1, Fig. 902) 2. Bring circulation pump (2) in assembly position and secure using clamp (3) and screws (4). 3. Torque screws (4) to 3 Nm ± 10%. 4. Make electrical connections (see 9.2.1.2). 5. Install heater (see 8.7.1.2). 1. 2. 3. 4. 5. Remove heater (see 8.7.1.1). Disconnect electrical connections (see 9.2.1.1). Remove screws (4, Fig. 902).
9 Repair Thermo 90 9.2.3 Replacement of Temperature Limiter 9.2.4 Replacement of Temperature Sensor 9.2.3.1 Removal 9.2.4.1 Removal NOTE Perform the following procedure only when the temperature limiter needs replacement. A functional check has to be performed when the temperature limiter is installed. 1. Remove heater (see 8.7.1.1). 2. Disconnect electrical connections (see 9.2.1.1). 1. Remove heater (see 8.7.1.1). 2. Disconnect electrical connections (see 9.2.1.1). 3. Remove clamp (2, Fig.
Thermo 90 9 Repair NOTE One of the newer models Thermo 90 shown. Older models have the cable of the temperature limiter located on the side. Heater Thermo 90 S may have the control unit located on the combustion air fan not affecting the replacement of the temperature limiter and temperature sensor. 1 2 3 4 5 6 0 9 mo er Th Protective Cap Clamp Temperature Limiter Heat Exchanger O-Ring Temperature Sensor 1 2 3 4 6 5 Fig.
9 Repair Thermo 90 9.2.5 Replacement of Combustion Air Fan 9.2.5.2 Installation 9.2.5.1 Removal NOTE Locate packing ring (3, Fig. 904) properly; do not squeeze. 1. 2. 3. 4. Remove heater (see 8.7.1.1). Disconnect electrical connections (see 9.2.1.1). Remove screws (2, Fig. 904). Pull combustion air fan (1) from burner head (4) and remove together with profiled packing ring (3). 1. Bring combustion air fan (1) with new profiled packing ring (3) in assembly position and secure with screws (2). 2.
Thermo 90 9.2.6 Replacement of Burner, Flame Sensor, and Glow Plug 9.2.6.1 Removal 1. 2. 3. 4. 5. 6. 7. 8. 9. Remove heater (see 8.7.1.1). Remove combustion air fan (see 9.2.5.1). Remove screw (5, Fig. 905) and washer (4). Remove nuts (10) and withdraw bracket. Withdraw grommets (11 and 12) from slots in housing of combustion tube (3). Withdraw grommet (13) and burner (1) from burner head and remove together with swirl ring (2). Pull flame sensor (7) and glow plug (6) out of burner (1) and remove.
9 Repair Thermo 90 1 2 3 4 5 6 7 8 9 10 11 12 13 1 13 12 11 6 7 0 9 mo 8 er Th 9 10 NOTE One of the newer models Thermo 90 shown. Older models have the cable of the temperature limiter located on the side. Illustration is also applicable for heater Thermo 90 S. 2 4 5 3 Fig.
Thermo 90 9 Repair 9.2.7 Replacement of Burner Head 9.2.7.2 Installation 9.2.7.1 Removal NOTE Burner head and exhaust outlet pipe can still be aligned during installation in vehicle. 1. Remove heater (see 8.7.1.1). 2. Remove combustion air fan (see 9.2.5.1). 3. Remove burner, flame sensor, and glow plug (see 9.2.6.1). 4. Remove attachment screw of V-clamp (2, Fig. 906) and pull off clamp. 5. Withdraw burner head (1) from heat exchanger (3) and remove. 6.
9 Repair Thermo 90 9.2.8 Replacement of Heat Exchanger 9.2.8.2 Installation 9.2.8.1 Removal 1. Clip connector housing onto heat exchanger and engage connector in connector housing. 2. Install burner head (see 9.2.7.2). 3. Install burner, flame sensor, and glow plug (see 9.2.6.2). 4. Install combustion air fan (see 9.2.5.2). 5. Install temperature sensor (see 9.2.4.2). 6. Install temperature limiter (see 9.2.3.2). 7. Install circulation pump (see 9.2.2.2). 8. Install heater (see 8.7.1.2). 1. 2. 3. 4.
Thermo 90 10 10 Packaging/Storage and Shipping Packaging/Storage and Shipping 10.1 General The heater and its components shipped to Webasto Thermosysteme GmbH for inspection or repair are to be cleaned and packaged so that they are protected against damage during handling, transportation, and storage. CAUTION Should a complete heater assembly be shipped it must be totally emptied. When packaging or shipping it must be ensured that no fuel or coolant is able to escape.
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