BoilerFaultCodesWhat the manual says
Manufacturer manualFault in Room Unit/Control Unit
Shared across the 800 System 2 range
This code is shared by the boilers in this range, which use the same control board. It may not be printed in this exact variant’s manual.
DIY fix possible
Check if the wireless room thermostat or control unit needs its batteries replaced.Power cycle the boiler and the control unit to re-establish their wireless or wired connection.Ensure the control unit is within range and not experiencing interference from other household electronics.
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Related fault codes
All 75 fault codes on the 800 System 2
Seeing a different code? Every code this model can display, in one place.
A.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 .06E.00 .07E.00 .16E.00 .17E.00.20E.00.21E.01.04E.01.12E.01.17E.01.20E.02.13E.02.15E.02.17E.02.35E.02.47E.04.00E.04.01E.04.02E.04.03E.04.07E.04.08E.04.09E.04.10E.04.11E.04.12E.04.13E.04.14E.04.15E.04.17E.04.18E.04.19E.04.20E.04.21E.04.23E.04.24E.04.54H.00.42H.01 .00H.01 .05H.01 .08H.01 .14H.01 .18H.01 .21H.02 .00H.02 .02H.02 .03H.02 .04H.02 .05H.02 .07H.02 .09H.02 .10H.02 .12H.02 .38H.02 .70H.03 .00H.03 .01H.03 .02H.03 .05H.03 .17H.03 .54