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Baxi Baxi 600/800/Assure System 2 and 600 Combi 2 platform fault H.01.21

Flow temperature increase in domestic water mode too quick

Gas boiler

What it means

Temporary stoppage of 10 minutes due to flow temperature increasing too quickly in domestic water mode

Likely causes

  1. Low installation pressure
  2. Air in system
  3. Faulty pump
  4. Poor circulation
  5. Faulty temperature sensors
  6. Poor sensor connection
  7. Worn or damaged venting valve seal

Where to start

  1. Check the installation pressure
  2. Check the operation of the pump
  3. Check the boiler/installation circulation

The full answer, free

  • 4 more checks in order
  • How to put it right, step by step
  • The manual page for this fault (page 74), right under the answer
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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 Baxi manual for the Baxi 600/800/Assure System 2 and 600 Combi 2 platform. Check the model on the data plate before you order parts.

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