Worcester Bosch Greenstar boilers use an aluminium heat exchanger with a sump at the bottom, and a fan and burner assembly on top. This is what our Gas Safe engineers do on a Worcester Bosch strip-down service. It covers Greenstar i, Si, CDi, 4000 and 8000 Life boilers.

Step by step

Isolate and open up. Turn off the gas, power and water, remove the case and check the fault history.
Remove fan and burner. Disconnect the gas and electrics, then remove the fan and burner assembly from the top of the heat exchanger.
Inspect the burner and gasket. Check the burner skin and the burner gasket. A damaged gasket is renewed before the boiler goes back together.
Clean the heat exchanger and sump. Clean the heat exchanger and remove the sump or inspection cover to clear the deposits that collect at the bottom.
Clean the condensate trap. Remove and clean the condensate trap and check the condensate pipe, which freezes in cold snaps on many Greenstar installs.
Check the electrode set. Inspect the electrode set for wear and correct gaps, and renew it if needed.
Rebuild and test. Reassemble, gas tightness test, then flue gas analysis against Worcester’s combustion limits.
Final checks. Check the expansion vessel, pressure relief valve, system pressure and controls.

Common Greenstar faults a strip-down helps prevent: EA 227 flame faults from a worn electrode or dirty burner, and blocked sump or condensate trap faults.

Price

A Worcester Bosch strip-down service is £175, or £260 with a landlord gas safety certificate on the same visit. If a seal, gasket or electrode needs renewing, we tell you the price before fitting it.

Book strip-down + certificate Strip-down only

Other boilers

See how a strip-down differs from a standard service.