Viessmann Vitodens 100-W fault 163

Checksum error, data memory access, HBMU heat management unit

Gas boiler

What it means

Burner in a fault state due to a checksum error during data memory access in the HBMU heat management unit.

Likely causes

  1. Checksum error, data memory access, HBMU heat management unit
  2. Burner locked out due to a fault condition

Where to start

  1. Reset the appliance.
  2. Tap up/down arrows to display the fault number
  3. Press up and down arrows simultaneously for approx. 4 seconds

The full answer, free

  • 2 more checks in order
  • How to put it right, step by step
  • The manual page for this fault (page 73), 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.

Other Viessmann Vitodens 100-W fault codes