Webasto Thermo 90 ST B Installation Manual
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Webasto Thermo 90 ST B Installation Manual

Webasto Thermo 90 ST B Installation Manual

Coolant heater
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Coolant Heater
Thermo 90 ST B (Gasoline)
Thermo 90 ST D (Diesel)

Installation Manual

– Improper installation or repair of Webasto heating and cooling systems can cause fire
or the leakage of deadly carbon monoxide leading to serious injury or death.
– Installation and repair of Webasto heating and cooling systems requires special
Webasto training, technical information, special tools and special equipment.
– NEVER attempt to install or repair a Webasto heating or cooling system unless you
have successfully completed the factory training course and have the technical skills,
technical information, tools and equipment required to properly complete the
necessary procedures.
– ALWAYS carefully follow Webasto installation and repair instructions and heed all
WARNINGS.
– Webasto rejects any liability for problems and damage caused by the system being
installed by untrained personnel.

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Summary of Contents for Webasto Thermo 90 ST B

  • Page 1: Installation Manual

    – Installation and repair of Webasto heating and cooling systems requires special Webasto training, technical information, special tools and special equipment. – NEVER attempt to install or repair a Webasto heating or cooling system unless you have successfully completed the factory training course and have the technical skills, technical information, tools and equipment required to properly complete the necessary procedures.

  • Page 3: Table Of Contents

    12.1 Thermo 90 ST Circuit Diagram Legend ............26 13.Initial Start-up 14.Troubleshooting www.webasto.us Webasto Product N.A., Inc.
  • Page 4 15.3 Fuel for Thermo 90 ST (Diesel): ..............31 16.Additional Installation Accessories www.webasto.us Webasto Product N.A., Inc.

  • Page 5: Safety And General Information

    1.2 General Information Webasto Product North America, Inc. is pleased to provide this installation manual for use with this new heater. When installed in accordance with the guidelines stated in this manual, you can expect to provide years of trouble-free, enjoyable operation for your customer.

  • Page 6: Regulation For Installation In The Vehicle

    2.2.6 A clearly visible indicator within the user's field exclude all risk of injury or damage caused by of vision must show when the heater is switched direct contact. on or off. Webasto Product N.A., Inc. www.techwebasto.com...
  • Page 7 Failure to follow the installation instructions and the notes contained therein will lead to all liability being refused by Webasto. The same applies if repairs are carried out incorrectly or with the use of parts other than genuine Webasto service parts. This will result in...

  • Page 8: Purpose / Version

    Water heater for "gasoline" fuel Thermo 90 ST diesel Water heater for "diesel" fuel The water heaters are designed for 12 V (Thermo 90 ST gasoline) and for 12 or 24 V (Thermo 90 ST diesel) Webasto Product N.A., Inc. www.techwebasto.com...

  • Page 9: Installation

    Thermo 90 ST Installation 4. Installation As a rule, installation in the engine compartment represents sufficient screening. Please contact the Webasto hotline in the event that radio interference IMPORTANT! occurs nevertheless. The water heater must be installed outside the passenger cabin.

  • Page 10: Installation Location Examples

    Installation Location Examples Thermo 90 ST 5. Installation Location Examples Figure 1: Installation locations Webasto Product N.A., Inc. www.techwebasto.com...

  • Page 11: Mounting The Heater To The Vehicle

    Figure 2: Allowable enclosure kit mounting positions, 1 and 2 only. Position 3 is not permissible. Figure 3: Permitted installation positions for the Thermo 90 ST heater - Enclosure and Compact Kits Figure 4: Permitted installation positions for the Thermo 90 ST heater - Compact Kits only www.webasto.us Webasto Product N.A., Inc.
  • Page 12 Do not weld vehicle frame or flanges! Figure 5: Drill frame within the shaded area only! 310mm (12-13/64”) 80mm (3-5/32”) 70mm (2-3/4”) 150mm (5-29/32”) 23mm (29/32”) 45mm (25/32”) Figure 6: Mounting heater enclosure via back wall (Vertical or horizontal mounting) Webasto Product N.A., Inc. www.techwebasto.com...
  • Page 13 Mounting the Heater to the Vehicle 150mm 150mm 484mm 363mm 158mm 500mm Figure 7: Optional perpendicular mounting with bracket kit P/N 905822 or P/N 905838 (Freightliner style) Figure 8: Optional cross-frame mounting bar/clamp kit P/N 600055 (Also see Figure 1) www.webasto.us Webasto Product N.A., Inc.

  • Page 14: Connection To The Vehicle Cooling System

    Separate the heater supply and return connections at the engine as far apart as Optimum Cross-Flow Through Engine is practical for optimum engine heating and heater performance. See Figure 9. Figure 9: Ensure optimum cross-flow Webasto Product N.A., Inc. www.techwebasto.com...

  • Page 15: Various Plumbing Configurations

    Figure 15 illustrates a system for vehicles with continuous fan operation or high amperage heat exchanger fan designs. In this case, the addition of a low amperage draw, auxiliary heat exchanger system is recommended. Webasto offers a complete kit under part number 905670 for this application.
  • Page 16 Figure 14: System configured with a bypass circuit within the rear heat exchanger circuit where an automated flow control valve is installed. Bypass is required in the event the valve is closed during heater operation. Webasto Product N.A., Inc. www.techwebasto.com...

  • Page 17: Additional Heating System Accessories

    7.3 Additional Heating System Accessories Webasto offers a line of Sleeper Pack Interface Wiring Kits that work with many OEM HVAC systems. These kits simplify the installation and pairing of the Webasto coolant heater with the vehicle’s own bunk heating system.

  • Page 18: Fuel Supply

    0 ° A. Fuel standpipe E. Fuel pump B. Connector hose F. Fuel line (Mecanyl) C. Fuel filter G. 90° Connector hose D. Hose clamp Figure 16: Fuel system components Webasto Product N.A., Inc. www.techwebasto.com...

  • Page 19: Fuel Standpipe Installation

    A. Fuel standpipe B. Compression fitting C. Hex nut D. Metal washer E. Rubber washer F. Tank boss 1/4” NPT Figure 19: Standpipe installation - illustration 1 G. 25mm (1”) hole Figure 18: Webasto fuel standpipe www.webasto.us Webasto Product N.A., Inc.

  • Page 20: Fuel Tank

    9. pull up on standpipe and tighten in place with the clamping nut (item A in Figure 22). Do not over- tighten causing rubber washer to squeeze out! Figure 20: Standpipe installation - illustration 2 Fuel Tank Figure 22: Standpipe installation - illustration 3 Webasto Product N.A., Inc. www.techwebasto.com...

  • Page 21: Fuel Lines

    The metering pump and fuel lines must not be installed within range of the radiated heat from hot vehicle parts. A heat shield must be used if necessary. Figure 23: Fuel line / coupler hose connection www.webasto.us Webasto Product N.A., Inc.

  • Page 22: Attachment

    8.5 Fuel Filter Only a Webasto filter is allowed to be used if the fuel is expected to be contaminated. Install vertically if possible, however at least horizontally (check flow direction).

  • Page 23: Combustion Air Supply

    The size of the ventilation opening must be increased accordingly if the temperature in the box exceeds the permitted ambient temperature of the heater (see Technical data). www.webasto.us Webasto Product N.A., Inc.

  • Page 24: Exhaust System

    The exhaust muffler is essential and must be installed near the heater. The exhaust muffler is secured to the heater using a coupler between the heater and muffler and a bracket fastened to the underside of the enclosure. See Figure 27 for details. Webasto Product N.A., Inc. www.techwebasto.com...
  • Page 25 If the exhaust line cannot be installed so that it slopes downwards at all points, a water drain hole with a diameter of 4 mm (5/32”) is to be made at its lowest point to allow condensate to drain. www.webasto.us Webasto Product N.A., Inc.

  • Page 26: Electrical Connections

    For sleeper and engine heating applications, Webasto recommends a four battery system for best results. A weather sealed fuse holder is to be fitted to protect the heater (supplied with the power / control harness).

  • Page 27: Connecting The Controls

    Thermo 90 ST Electrical Connections 11.2 Connecting the Controls The heater can be switched on and off using the following Webasto controls: • Switch, see circuit diagrams in Figures 30 and 32. • Timer, see circuit diagrams in Figures 31 and 33.

  • Page 28: Circuit Diagrams

    To X9 of item P2 Plug connector, 1-pin To pin-10 of item X9 (see Plug connector, 3-pin To optional blower interface systems (Sleeper Pak™) 5-pin relay socket Vehicle fan interface harness option Metering pump Fuel pump for heater Webasto Product N.A., Inc. www.techwebasto.com...
  • Page 29 Thermo 90 ST Circuit Diagrams Figure 32: Thermo 90 ST with On/Off switch - connection diagram (Includes optional blower interface harness) www.webasto.us Webasto Product N.A., Inc.
  • Page 30 Circuit Diagrams Thermo 90 ST Figure 33: Thermo 90 ST with 7-day digital timer model 1531 - connection diagram Webasto Product N.A., Inc. www.techwebasto.com...

  • Page 31: Initial Start-Up

    Conduct a trial of the heater to check all the water and fuel connections for leaks and to ensure that they are secure. If the heater suffers a fault during operation, the fault must be located and remedied. www.webasto.us Webasto Product N.A., Inc.

  • Page 32: Troubleshooting

    F 08 Blower motor interrupt or blower motor short- circuit or blower motor incorrect speed F 09 Glow plug interrupt or glow plug short-circuit F 10 Overheating F 11 Circulating pump interrupt or circulating pump short-circuit Webasto Product N.A., Inc. www.techwebasto.com...

  • Page 33: Technical Data

    Heater dimensions (tolerance ± 3 mm) L 307 (352*) mm * Control module installed on the heater W 131 mm H 232 mm Weight 4,8 kg Table 1: Technical Data - Metric Measurement www.webasto.us Webasto Product N.A., Inc.
  • Page 34 * Control module installed on the heater W 5.157 inch H 9.13 inch Weight 10.58 lb. Table 2: Technical Data - US Standard Measurement 24 V XXXXXXX_.XXXXX Figure 34: Thermo 90 ST control module, arbitrary installation position Webasto Product N.A., Inc. www.techwebasto.com...
  • Page 35 Thermo 90 ST Technical Data Thermo 90 ST ø20 ø39 ø5 ø20 ø30 ø38 ø74 Combustion air intake Exhaust outlet Fuel inlet pipe Coolant inlet Coolant outlet Figure 35: Dimensions of the Thermo 90 ST Heater www.webasto.us Webasto Product N.A., Inc.

  • Page 36: Additional Installation Accessories

    Kenworth AeroCab and Studio Sleeper built before September 1996, Mack CL, CH, Vision, Peterbilt model 387, Sterling - all, Volvo VN, WIA, Western Star - all. Call your Webasto representative for information or questions regarding “Sleeper Pack” systems. Webasto Product N.A., Inc.
  • Page 37 Thermo 90 ST Notes www.webasto.us Webasto Product N.A., Inc.
  • Page 38 Notes Thermo 90 ST www.webasto.us Webasto Product N.A., Inc.
  • Page 39 Thermo 90 ST Notes www.webasto.us Webasto Product N.A., Inc.
  • Page 40 Webasto Product N.A., Inc. 15083 North Road Fenton, MI 48430 Technical Assistance Hotline USA: (800) 860-7866 Canada: (800) 667-8900 www.techwebasto.com Org. 01/2007 Rev. 05/2007 P/N 5000994A © 2007 Webasto Product N.A., Inc. www.webasto.us...

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