TradeAssistIQHome

Vokera Synergy fault AF1

DHW anti-freeze function active

Gas boiler

What it means

DHW anti-freeze protection function. Starts if the temperature detected by the DHW probe falls below 5°C. A heat request is generated with burner ignition at minimum output, maintained until water delivery temperature reaches 55°C. Display shows AF1.

Likely causes

  1. Low ambient/system temperature near freezing
  2. DHW probe detecting temperature below 5°C
  3. Flue components incorrectly assembled, fixed or supported
  4. Flue or flue terminal obstructed
  5. Degraded seals around appliance burner, internal flue, door or case
  6. Maximum flue lengths exceeded or guidance (e.g. Technical Bulletin 008) not followed
  7. Analyser not zeroed/calibrated correctly before use

Where to start

  1. Confirm electrical supply and fuel supply remain active
  2. Check DHW probe temperature reading
  3. Check system water pressure is at least 0.4 bar to ensure water pressure switch is activated; insufficient pressure prevents pump and fan operation and triggers low-pressure fault code

The full answer, free

  • 33 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 36), right under the answer
Ask about AF1 freeCreate a free account

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 Vokera manual for the Synergy. Check the model on the data plate before you order parts.

Other Vokera Synergy fault codes