Medium
H.01.21 on Baxi Assure System

Your boiler is heating water too quickly, which is triggering a safety shut-down to prevent the system from overheating.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

Book a service

This fault should be looked at by a Gas Safe engineer within the next week or two. It may get worse if left.

What the manual says

Manufacturer manual

Flow temperature increase during domestic hot water operation too fast. iNSUFFICIENT CIRCULATION Check the installation pressure Activate a manual venting cycle Check the operation of the pump Check the boiler/installation circulation TEMPERATURE SENSOR ERROR Check the operation of the temperature sensors Check the temperature sensor connection

From this model's manual
Verified against the Baxi/Baxi Bm Baxi B Basic System 2 600 800 Assure 500 Isim installation & service manual, page 49.
Plain-English guidance below. Severity, DIY steps, costs and parts are our interpretation to help you act, not text from the manual.

Engineer required

This fault requires a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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All 66 fault codes on the Assure System

Seeing a different code? Every code this model can display, in one place.

101213A.00.28A.00.29A.00.34A.02.06A.02.18A.02.36A.02.37A.02.45A.02.46A.02.48A.02.49A.02.54A.02.55A.02.76E.00 .04E.00 .05E.00 .16E.00 .17E.00 .20E.00 .21E.01 .04E.01 .12E.01 .17E.01 .20E.02 .13E.02 .17E.02 .35E.02 .39E.02 .47E.04 .01E.04 .02E.04 .08E.04 .12E.04 .13E.04 .17E.04 .18E.04 .23E.04 .29E.04 .54E.04 .254E.04.03E.04.10H.00.42H.00.81H.01 .14H.01.00H.01.05H.01.08H.01.18H.02 .00H.02 .02H.02 .03H.02 .04H.02 .05H.02 .09H.02 .10H.02 .70H.02.07H.03 .00H.03 .05H.03 .54H.03.02

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