Glow-worm Energy Combi fault F.49

EBUS fault: voltage too low

Gas boiler

What it means

eBUS voltage detected as too low

Likely causes

  1. Short circuit on eBUS
  2. EBUS overload
  3. Two power supplies with different polarities on the eBUS

Where to start

  1. Check d.80 for running time in heating mode (display value x100 hours)
  2. Check d.81 for running time in DHW mode (display value x100 hours)
  3. Check d.82 for number of burner ignitions in heating mode (display value x100)

The full answer, free

  • 3 more checks in order
  • The readings and component tests from the manual
  • How to put it right, step by step
  • The manual page for this fault (page 52), 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 Glow-worm manual for the Energy Combi. Check the model on the data plate before you order parts.

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