Viessmann Vitodens 050-W: no heating or hot water — what to note

If your Viessmann Vitodens 050-W has stopped providing heating, hot water or both, the most useful first step is to record exactly what has happened.

Vitodens 050-W is a boiler family rather than one single appliance and control setup. Viessmann’s current UK range includes combi and system versions, several outputs and versions that may use different controls. Advice for the wrong version can send you in the wrong direction.

This guide helps you collect the right information for a repair enquiry. It does not give a reset, repressurising or internal repair procedure.

Confirm which Vitodens 050-W you have

Viessmann’s current UK product information lists the Vitodens 050-W as both a combi and a system boiler. The current combi type is identified as B0KA on the manufacturer’s product page, while the exact type and revision in your home still need to be matched from the appliance record.

Use your installation paperwork, Benchmark record, warranty information or a safely visible appliance label to note:

1. The full product name.
2. Whether the installation is recorded as combi or system.
3. The stated output.
4. The article or serial number, if it is safely visible.
5. The make and model of the room thermostat, receiver or app.

Viessmann’s serial-number locator says the 16-digit number for the Vitodens 050-W is on top of the boiler. Only look if the area is safely visible from floor level. Do not climb, remove the case or reach around the appliance.

Record whether heating, hot water or both are affected

These symptoms can point to different parts of the system, so be specific:

• No heating, but hot water still works.
• Heating works, but there is no hot water.
• Neither heating nor hot water works.
• The problem is intermittent.
• One room or one tap is affected rather than the whole home.

Note when the problem started and whether it followed a power cut, a control change, building work or another event. This does not diagnose the fault, but it gives the engineer a clearer starting point.

Photograph the display before changing anything

The current Vitodens 050-W product page describes a digital display with touch buttons. Depending on the version, the boiler may also use ViCare or a separate room control.

Take a clear photograph of the boiler display and write down every visible code, symbol or message exactly as shown. Also photograph the room control or app screen if it is part of the problem.

Fault-code meanings can differ between boiler models and revisions. Do not use a code table or button sequence for a different Vitodens model. The correct operating instructions should be matched using the article or serial number in Viessmann’s ViBooks database.

Do not guess the reset or filling procedure

The installed filling arrangement, control setup and permitted reset action must be confirmed for the exact appliance and revision.

Do not remove the casing, touch internal wiring or gas controls, enter installer or service menus, bypass a safety device or keep resetting a fault that returns. Do not add water to the system if there is a visible leak.

If pressure is repeatedly lost, water is leaking, the appliance becomes unusually hot, a fault returns or the boiler does not respond normally, stop and arrange professional help.

Gas smell or carbon monoxide concern

A smell of gas, a carbon monoxide alarm or possible carbon monoxide symptoms is an emergency, not an ordinary boiler fault.

If you smell gas, SGN says to open windows and doors, avoid smoking or naked flames, do not touch electrical switches and call the National Gas Emergency Service on 0800 111 999.

If you are worried about carbon monoxide, open doors and windows, move everyone into fresh air and call 0800 111 999. If anyone has collapsed or has severe symptoms, call 999 or 112 for medical help.

What to send with a repair enquiry

Before contacting a repair company, gather:

1. The boiler name, type, output and serial or article number you can safely identify.
2. A photograph of the full display.
3. The exact fault code or message.
4. Whether heating, hot water or both are affected.
5. The controller or thermostat make and model.
6. Any visible water leak or repeated pressure loss.
7. When the problem started and whether it is constant or intermittent.
8. Your most recent service information, if available.

This evidence can help the office understand the appliance and arrange the right next step. It is not a remote diagnosis or a confirmed appointment.

MPH Boilers can help with boiler repairs and fault finding. If the boiler is due routine maintenance rather than a repair, read what a boiler service involves. Tell the team your postcode and appliance details so they can confirm coverage and availability.

Frequently asked questions

Is every Vitodens 050-W a combi boiler?

No. Viessmann’s current UK range includes combi and system versions. Match advice to the exact appliance and installation.

Should I reset the boiler before taking a photograph?

No general reset is authorised by this guide. Record the display first and use only the action permitted by the current operating instructions for your exact appliance.

Can I use a Vitodens 100-W fault guide for a 050-W?

No. Fault meanings and controls can vary between models and revisions. Use the correct 050-W documentation matched by article or serial number.

What if the display is blank?

Record that the display is blank and whether other parts of the home have power. Do not remove the boiler case or touch internal electrical parts. If the boiler remains unresponsive, arrange professional help.

Should I keep topping up pressure if it falls again?

No. Repeated pressure loss or a visible leak needs investigation. Do not keep adding water and do not attempt to repressurise a leaking system.

Sources and applicability

• Viessmann UK, “Vitodens 050-W wall mounted gas condensing boiler”: https://www.viessmann.co.uk/en/products/gas/vitodens-050-w.html. Current UK family, combi/system distinction, outputs, B0KA combi type, display and version-dependent connectivity. Retrieved and read 23 October 2026.
• Viessmann UK, “Instruction manuals”: https://www.viessmann.co.uk/en/support/manuals.html. ViBooks search by article or serial number. Retrieved and read 23 October 2026.
• Viessmann UK, “Serial Number Locator: Vitodens 050-W”: https://www.viessmann.co.uk/en/support/spare-parts-app/serial-number-locator-for-viessmann-products/serial-number-locator-vitodens-050-W.html. External serial-number location only. Retrieved and read 23 October 2026.
• Viessmann UK, “How to check and fix boiler fault codes”: https://www.viessmann.co.uk/en/heating-advice/boilers/how-to-check-and-fix-boiler-fault-codes.html. Supports the model-specific manual boundary and professional escalation; it is not used for a 050-W button sequence. Retrieved and read 23 October 2026.
• Viessmann UK, “We are here to help”: https://www.viessmann.co.uk/en/support/after-sales-support.html. Professional support and gas-emergency boundary. Retrieved and read 23 October 2026.
• SGN, “Gas safety”: https://www.sgn.co.uk/help-and-advice/keeping-gas-safe/gas-safety. Gas smell and carbon-monoxide emergency steps for Scotland, including 0800 111 999 and medical escalation. Retrieved and read 23 October 2026.