After Sales Support for Installers & Professionals

With our comprehensive after sales support, we are here to help. Should you require support with your Viessmann heating system, we are always able to provide it.

At Viessmann, we are constantly striving to offer a world class service in every area and draw on our experience gained over 100 years to do this. We work tirelessly to support our heating installations across all fuel types and applications, responding to the needs of our customers nationwide. However, should a problem develop with a Viessmann product, then the re-assurance you have is that we are here to help. 

To assist you in installing, servicing and maintaining our products, technical guides, installation instructions and operating instructions are available to download in PDF format from our online database.

Technical helpline

Viessmann Customer Service Team

Our Customer Service team is here to help you get the best from your Viessmann product throughout its lifetime. Whatever your enquiry, simply call one of our specialist advisors in Telford, email us, or book a visit from a Viessmann Service Engineer if you'd like someone to come to you.

We are here to help you get the most out of your Viessmann system throughout its lifecycle.

Boiler Service Checklist

This service checklist below meets industry agreed best practise as outlined in the Heating & Hotwater Industry Council Gas Boiler Servicing guide.

  • Check operation of the boiler and controls before service begins to ensure safe operation. 
  • Electrical safety test and tightness of electrical connections at appliance.
  • Burner removed and heat exchanger cleaned.
  • Check burner gaskets and general condition.
  • Check condition of Ignition and Ionisation electrodes.
  • Check condensate siphon/drain and clean.
  • Check expansion vessel and system pressure. If necessary repressurise.
  • DHW flow rate check.
  • Carry out gas safety checks to ensure the boiler is operating to specification.
  • Flue gas emissions test.


Our customer services and technical teams are happy to talk you through any questions you may have relating to your Viessmann product including our gas condensing boilers, heat pumps, fuel cell, oil and combined heat and power. To receive the support you require, please see the telephone numbers and email addresses below, and contact the one that is most relevant to your enquiry.

You may also wish to use our online Fault Code Identifier tool.

Customer services

Our customer services number is the best number to call should you wish to book a service engineer visit, or should you have any non-technical questions relating to our products or services.

ErP Advice

Opening times

  • Monday to Friday from 8:30 am to 5.00 pm*

* Outside office hours, after sales calls are routed to a call handling service. We can reply to these on the next working day.