What does the Worcester Bosch 1021 fault code mean?

Your boiler is struggling to accurately measure the temperature of your hot water, which usually means your taps aren't getting hot enough or stay cold.

How much does it cost to fix Worcester Bosch error code 1021?

Typical repair cost for the Worcester Bosch 1021 fault is £110-180 including labour.

Worcester Bosch 1021 Fault Code: What It Means & How to Fix It

What the manual says

Manufacturer manual

Cylinder charging or hot water temperature sensor faulty

Shared across the Greenstar 8000 Life 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.

What causes this fault?

This fault occurs when the boiler's internal computer stops receiving a reliable signal from the sensors that monitor your hot water temperature. The most common reason is that the sensor has either worn out internally or a connection in the wiring has become loose or corroded, preventing the boiler from knowing when to fire up to heat your water.

Engineer required

This is a high severity fault. Stop using the boiler and call a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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Boiler cover options

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Related fault codes

1017View →

All 151 fault codes on the Greenstar 8000 Life Combi

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

1-A1 1-A2 1-A3 1-A5 1-A6 1-A7 1-b2 1-b3 1-b4 1-b7 1-b8 1-C1 1-C2 1-C4 1-C6 1-d1 1-d2 1-d3 1-d4 1-d5 1-E1 1-E2 1-E3 1-E4 1-EA 1-Eb 200 200 O 201 201 O 202 202 O 203 204 204 O 208 214 224 224 V 227 227 V 228 228 V 229 232 233 234 235 237 238 242 244 245 249 250 251 252 253 254 257 258 259 262 263 265 268 269 273 281 283 284 305 306 306 V 357 358 360 360 V 362 363 604 815 1010 1010 O 1013 1017 1017 W 1018 1019 1021 B 1023 1025 1037 1037 W 1065 1065 B 1068 1068 W 1070 1071 1072 1075 1075 W 1076 1076 W 2085 2908 2910 2914 2915 2916 2920 2920 V 2923 2924 2925 2926 2928 2931 2940 2946 2946 V 2948 2948 B 2949 2950 2950 B 2951 2952 2955 2956 2957 2961 2962 2963 2963 B 2965 2965 B 2966 2966 B 2968 2969 2970 2970 B 2971 2971 B 2972 A-A5 A-b2 A-b4

Your boiler is struggling to accurately measure the temperature of your hot water, which usually means your taps aren't getting hot enough or stay cold.

What the manual says

What causes this fault?

Engineer required

Avoid the next call-out bill

Related fault codes

All 151 fault codes on the Greenstar 8000 Life Combi

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