Webasto Thermo Pro 90

Other manuals for Webasto Thermo Pro 90

Installation Instructions35 pages

Questions and Answers

M
Mr. Jason MayerAug 13, 2025
How to fix a heater lock-out on a Webasto Water Heater?
- T
  Tyler JonesAug 13, 2025
  If you experience a heater lock-out with your Webasto Water Heater, there are several actions you can take. First, clear the error memory using the "Clear fault memory and heater interlock" command located in the "Error memory" menu. Alternatively, you can delete the heater lock-out by clicking the "Delete heater lock-out" button, also found in the "Error memory" menu. As another option, you can remove fuse F3 for at least 10 seconds and then reinstall it.
S
Shannon JacksonAug 17, 2025
Why does my Webasto Thermo Pro 90 Water Heater smell like fuel?
- J
  James PatrickAug 17, 2025
  If your Webasto Water Heater exhibits fuel odor, check the fuel lines for leaks, kinking, and clogging. Pay special attention to the area around the intake-side line connectors.
D
Deborah Blake MDAug 21, 2025
What to do if Webasto Thermo Pro 90 Water Heater has coolant loss?
- R
  reginaldmontoyaAug 21, 2025
  If you notice coolant loss in your Webasto Water Heater system, inspect the heater, water connection piece, circulation pump, and hoses for leaks, and repair as necessary.
R
Robert JohnsonAug 25, 2025
Why Webasto Water Heater does not start and operation indicator flashes?
- S
  Scott DavisAug 25, 2025
  If your Webasto Water Heater is not starting, experiences a short start-up, and then immediately switches into run-on with a flashing operation indicator, the fuel supply should be checked.
V
vdavidAug 28, 2025
How to stop exhaust odour in vehicle interior from Webasto Thermo Pro 90?
- S
  Stephanie AustinAug 28, 2025
  If you smell exhaust odor inside your vehicle when using the Webasto Water Heater, verify that the intake and exhaust pipes are routed according to the general installation instructions.
J
John BlackwellSep 1, 2025
What to do if Webasto Thermo Pro 90 Water Heater switches off prematurely?
- M
  Michelle AndersonSep 1, 2025
  If your Webasto Water Heater runs through the start-up process but switches off prematurely, inspect the wiring for any damage, open circuits, or short circuits.
Y
Yolanda Wood DDSSep 4, 2025
Why Webasto Water Heater does not react and no display?
- C
  Charles ClementsSep 5, 2025
  If the Webasto Water Heater does not react, with no components starting and no display on the operation indicator, check the continuity and seating of the flat spring contacts on the metering pump line. Also, measure the cold resistance of the DP42 metering pump at 25 °C.
J
Jose DurhamSep 8, 2025
Why Webasto Thermo Pro 90 Water Heater has rough combustion?
- J
  Janice WatsonSep 8, 2025
  If your Webasto Water Heater has rough combustion, check the continuity and seating of the flat spring contacts of the metering pump line.

Summary

Introduction to Webasto Thermo Pro 90

Contents and Purpose of Manual

This workshop manual supports instructed personnel in repairing the Thermo Pro 90 water heater.

Meaning of Signal Words

Defines signal words like WARNING, IMPORTANT, and NOTE used throughout the manual.

General Safety Precautions

Covers accident prevention, works safety, statutory regulations, and specific safety guidelines.

Spare Parts Information

Information on where to find spare part numbers in the Webasto spare parts catalogue.

General Description of Thermo Pro 90

Combustion Air Fan Function

Describes the role of the combustion air fan in providing air for combustion.

Heat Exchanger Operation

Explains how heat generated by combustion is transferred to the coolant circuit.

Burner Unit Components

Details the burner unit where fuel evaporation and pre-combustion occur.

Circulation Pump Function

Describes the circulation pump's role in moving coolant within the vehicle.

Control Unit Functionality

Explains the control unit's role in managing operation and monitoring combustion.

Metering Pump System

Details the metering pump's function in fuel supply and as a shut-off system.

Description of Operation

Switching On and Residual-Heat Utilisation

Details how the heater is switched on and how residual heat is utilized.

Starting and Control Mode

Explains the heater's start-up sequence and regulated operating modes.

Heater Switch Off Procedure

Describes the process of shutting down the heater and its run-on phase.

Functions in ADR Vehicles

Outlines specific operational functions and modes for ADR-compliant vehicles.

Technical Data for Thermo Pro 90

Faults and Troubleshooting Guide

Troubleshooting Without Error Codes

Steps for diagnosing and resolving faults when no error code is displayed.

Troubleshooting With Error Codes

Procedures for diagnosing faults using error codes from the control unit or diagnostic tools.

Visual Inspection of Burner Unit

Guidelines for visually inspecting the burner unit for damage and wear.

Operating Tests and Checks

Vehicle Operating Checks

Performing routine operational checks of the heater within the vehicle.

Adjusting CO2 Content

Procedure for checking and adjusting the CO2 content for optimal combustion.

Checking Individual Components

Tests for verifying the functionality of specific heater components.

Circuit Diagrams

Servicing Work Procedures

Work on the Heater

General procedures and precautions for performing work on the heater itself.

Heater Removal and Installation

Step-by-step instructions for removing and reinstalling the heater unit.

Recommissioning After Installation

Steps for recommissioning the heater after installation and bleeding systems.

Maintaining and Replacing Components

Replacing Circulation Pump

Detailed instructions for removing and installing the circulation pump.

Replacing Overheating Protection

Guide for replacing the overheating protection component.

Replacing Coolant Temperature Sensor

Instructions for replacing the coolant temperature sensor.

Replacing Combustion Air Fan

Steps for removing and installing the combustion air fan.

Replacing Burner Unit and Glow Plug

Instructions for replacing the burner unit and the glow plug.

Replacing Heat Exchanger

Procedure for removing and installing the heat exchanger.

Replacing Exhaust Temperature Sensor

Guide for replacing the exhaust temperature sensor.

Packing, Storage, and Shipping Guidelines

General Packing and Shipping

General guidelines for protecting the heater during transport and handling.

Heater Storage Recommendations

Instructions for proper storage of the heater to prevent damage and contamination.

Transport Procedures

Guidelines for safely transporting the heater, including fluid drainage and protection.