Worcester Bosch Greenstar CDi Classic and 34CDi Repair London

Worcester Bosch Greenstar CDi Classic — London Repair Specialist

The Worcester Bosch Greenstar CDi Classic range was one of the most popular boiler ranges sold in the UK between approximately 2008 and 2018. The 25CDi, 28CDi, 32CDi and the particularly popular 34CDi are found throughout London in houses, flats and landlord properties across every borough. These boilers are now between six and sixteen years old, placing many of them at the point where repairs are becoming more common. Your local Worcester Bosch specialist at 247 Plumber London repairs and services the full CDi Classic range across London every day.

CDi Classic Models

Model	Output	Best For
Greenstar 25CDi Classic	25 kW	Flat or smaller house, 1 bathroom
Greenstar 28CDi Classic	28 kW	1 to 2 bed house, 1 bathroom
Greenstar 32CDi Classic	32 kW	2 to 3 bed house, 1 to 2 bathrooms
Greenstar 34CDi Classic	34 kW	2 to 4 bed house with higher hot water demand
Greenstar 40CDi Classic	40 kW	Large house, multiple bathrooms

The Greenstar 34CDi — London’s Favourite Larger Combi

The 34CDi deserves a special mention because of how widely it was installed across London in medium to large terraced houses. Its 34kW output gave it excellent hot water delivery at multiple outlets simultaneously, making it the default choice for London properties with two or more bathrooms throughout the late 2000s and 2010s. Many 34CDi boilers installed during that period are now at the age where component failures are more frequent, and we attend 34CDi breakdowns across London on a very regular basis.

Common CDi Classic Faults

Diverter Valve Failure

This is the single most common repair on CDi Classic boilers of seven years or more. The diverter valve O rings degrade with age and allow water to bypass the valve, meaning the boiler either heats the radiators when only hot water is called for, or delivers lukewarm hot water because heating circuit water is diluting the hot water circuit. Diverter valve replacement on the CDi Classic is a well practised repair and we carry the complete valve assembly for all CDi outputs.

EA 227 — Ignition Fault

Ignition faults are common on CDi Classic boilers that have not been serviced regularly. Electrode replacement resolves the majority of EA 227 lockouts on CDi boilers.

2970 — Fan Fault

Fan faults become more common on CDi Classic boilers after ten years. The fan pre-purges the heat exchanger before ignition and if it is not reaching the correct speed the boiler will not attempt to light. A noisy fan is often the early warning. Fan replacement is the standard repair.

CE 207 — Electrode or Ionisation Fault

The flame sensing circuit is not reading correctly. Either the electrode itself, the cable, or a dirty burner producing an inconsistent flame. We carry sensing electrodes for all CDi Classic outputs.