Viessmann Vitodens 100-W fault 100

PlusBus voltage error

Gas boiler

What it means

Electronics modules connected to PlusBus are not functioning due to a PlusBus voltage error.

Likely causes

  1. PlusBus power supply fault on HBMU heat management unit
  2. More than 1 Vitotrol 200-E connected to the HBMU
  3. Short circuit at the PlusBus cable

Where to start

  1. Check whether the PlusBus power supply on the HBMU heat management unit is OK: remove all connected PlusBus components and reconnect one by one
  2. Check that no more than 1 Vitotrol 200-E is connected to the HBMU
  3. Check whether there is a short circuit at the PlusBus cable

The full answer, free

  • How to put it right, step by step
  • The manual page for this fault (page 72), right under the answer

Safety: Isolate gas and power before you open the case. If you have been into the gas side, do a tightness test, and a combustion and flue check before you hand back. Gas Safe (UK) or RGI (Ireland) work only.

From the Viessmann manual for the Vitodens 100-W. Check the model on the data plate before you order parts.

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