Emergency
Group 1, 5 flashes on Worcester Bosch Greenstar CDi Compact

Your boiler has detected a potential internal gas leak or a sensor fault that prevents it from starting safely to protect your home.

Reviewed by the BoilerFaultCodes Editorial Team · Last reviewed

Act immediately

Turn off your boiler and stop using gas appliances. Call a Gas Safe engineer now. This fault can be dangerous if ignored.

What the manual says

Manufacturer manual

Ionisation detected after burner stopped; Gas valve leaking; False flame detected; Gas valve EV2 leak test failed; Gas valve EV1 leak test failed; Ionisation current detected before burner-start; Gas valve error; Ionisation sensor shorted

From this model's manual
Verified against the Greenstar 27 30 RiCompact ErP installation & service manual.
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 is a emergency severity fault. Stop using the boiler and call a Gas Safe registered engineer. Do not attempt gas-related repairs yourself.

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Related fault codes

EAView →

All 359 fault codes on the Greenstar CDi Compact

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

1.A1.C1.d1.E2.b2.C3.b3.C3.E3.F5.A8.C8.E8E9.E9.F9U1012131415202130404243535456100101102103104117118119121122123124125126127128131132133170171200201202203204205207207 / CE208210210 / E9211212213213 / D4214214 / C7215215 / C6216216 / C6217217 / C7218218 / E5219219 / E9220220 / E9221221 / E9222222 / E2223223 / E2224224 / E9225227227 / EA228228 / F7229229 / EA230230 / EA231231 / FD232232 / D3233233 / 9U234234 / EA237237 / C4238238 / F0238 F0239239 / F0239 F0240240 / D1240 D1241241 / D1241 D1242256257257 / b7257 b7258259260261261 / EA261 EA262263264264 / C1264 C1265266266 / CE266 CE267267 / F0267 F0268269269 / EA269 EA270271271 / D4271 D4272272 / F0272 F0273273 / C4273 C4274276276 / E9276 E9277277 / E9277 E9278278 / F0278 F0279279 / F0279 F0280280 / F0280 F0281281 / A1281 A1282282 / H5282 H5283284285285 / E9285 E9286286 / D1286 D1287287 / F0287 F0288288 / CF288 CF289289 / CF289 CF290290 / F0290 F0305306306 / FA306 FA307308309310311312313314315316316 / E9316 E9317317 / A3317 A3318318 / E9318 E9321322323323 / A8323 A8324325326327328329329 / CE329 CE332332 / E5332 E5333338338 / F0338 F0341341 / D4341 D4342342 / D4342 D4343343 / ED343 ED344344 / ED344 ED345345 / EF345 EF346346 / EC346 EC347347 / E3347 E3348348 / EE348 EE349349 / EF349 EF350350 / E2350 E2351354357358359364364 / FA364 FA365365 / Fb365 Fb372373373 / 8C373 8C374374 / 8C374 8C375375 / E4375 E4376376 / E4376 E4380800800 / CC800 CC808808 / A7808 A7810828A1A1 281A7A8b1b7Blue indicator (2) will flashC1C1 264C4C4 273C6C7D1D1 240D4D4 271E2E5E9E9 219E9 224EAEA 227EFEF 349F0F0 237-239F7F7 228FAFA 306FA 364FbFb 365FdFD 231Group 1, 1 flashGroup 1, 2 flashesGroup 1, 3 flashesGroup 1, 4 flashesGroup 2, 6 flashesGroup 2, 7 flashesGroup 2, 8 flashesGroup 2, 9 flashesGroup 2, 10 flashesRed LED five flash sequenceRed LED two flash sequenceSEt1t2t3t4t6

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