Low Warning
98:1 on Viessmann Vitodens 200-W

Your boiler is experiencing a communication error with an external remote monitoring system, meaning the central hub cannot correctly read your heating data.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

Monitor it

This is a minor fault. Keep an eye on it and mention it at your next annual boiler service. Reset the boiler and see if it clears.

Technical description

Viessmann system numbers (in conjunction with monitoring of several systems via Vitocom 300)

What causes this fault?

This fault occurs when the boiler's main control board loses its digital connection with an external monitoring system like the Vitocom module. It is usually caused by a loose communication cable, a damaged internal coding plug, or a hardware failure within the remote monitoring interface itself.

DIY fix possible

Check the power supply to the Vitocom 300 communication moduleEnsure the LAN or internet cable is securely plugged into the moduleReset the communication module by turning it off and back on again

Find a Gas Safe engineer
Search the official register →

Related guides you might find useful

Yellow or orange flame — CO safety

Safety-critical — turn off, read this.

Read →

Is boiler cover worth it?

Break-even maths on monthly cover.

Read →

When to replace your boiler

7 signs repair isn't worth it anymore.

Read →