BoilerFaultCodesWhat the manual says
Manufacturer manualFault: No pressure change detection when starting pump. Water pressure sensor and/or pump defective, air in the heating installation, insufficient water in the product; check adjustable bypass, connect external expansion vessel to the return
From this model's manual
Verified against the Vaillant/Vaillant Vaillantpro Ecofit Sustain Open Vent Installation And Servicing installation & service manual.
Engineer required
This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.
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All 36 fault codes on the ecoFIT sustain 415
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