Worcester Bosch Boiler Repairs London

Is gas working at other appliances in your home? If not, check your meter and any prepayment credit.

Pressure should read around 1.0 to 1.5 bar when cold. If below 1 bar, you may need to repressurise using the filling loop.

Is the room thermostat set above current room temperature? Are the batteries working?

Is the heating scheduled to be on? Check the clock is set correctly.

Locate the reset button on your Worcester boiler. Press once and wait. If the fault returns, do not keep resetting. Call an engineer.

In cold weather, the external condensate pipe can freeze. Look for a white plastic pipe exiting through an outside wall. If frozen, pour warm water over it gently.

The most common Worcester code. The boiler attempted to light but no flame was proved. Worcester's own manual says to check whether the gas is on elsewhere in the house, whether the condensate pipe is frozen, and whether the flue outlet is blocked, but only where it is safe to do so. Reset once. If EA returns, call an engineer.

The numeric equivalent of EA on EMS controlled models. Same checks: gas on elsewhere, condensate not frozen. Reset once only, then call an engineer.

The boiler still sees a flame signal after the gas valve has closed. Do not reset repeatedly and do not ignore it. Turn the boiler off at the controls and call an engineer.

A flame signal is present when the burner should be shut down. Like FA, this is a gas safety fault. Switch the boiler off and call an engineer.

Worcester's manual wording is that the safety temperature limiter in the central heating flow has tripped. The boiler has reached an unsafe temperature and locked out deliberately. Usually poor circulation, a failing pump, sludge, or a blocked heat exchanger. Do not keep resetting a limiter lockout. Call an engineer.

The numeric equivalent of E9. Same cause and the same rule: do not keep resetting. Call an engineer.

The flow temperature has climbed past its permitted level, often for the same reasons as E9. Call an engineer.

The flow sensor is reading incorrectly or has failed. Reset once. If it returns, call an engineer to test the sensor and its wiring.

The return temperature sensor has a fault. The boiler cannot judge the temperature difference across the system safely. Call an engineer.

The domestic hot water sensor has failed. You may get heating but unreliable hot water. Call an engineer.

Also shown as 1017 or 2971 on newer models. Top the system up through the filling loop to between 1.0 and 1.5 bar with the boiler cold. If it drops again within days there is a leak, a weeping pressure relief valve, or a failed expansion vessel. Call an engineer to find it.

The pump is seized, airlocked, or the system has lost water. Check the pressure gauge first. If pressure is correct and A1 stays, call an engineer.

Where a condensate pump is fitted, it has failed and the boiler has stopped to avoid an overflow. Call an engineer.

The fan is not running at the speed the boiler expects, so combustion cannot be proved safe. Call an engineer. Never remove the casing or work on a flue yourself.

The fan has not started, so the boiler will not attempt ignition. Call an engineer.

The fan stopped while the burner was running. The boiler locks out immediately. Call an engineer.

The most harmless code on the list. The reset was pressed when there was no fault. Press reset once more and the boiler should return to normal.

The code plug that tells the control board which boiler it is fitted to is missing, loose or unreadable. Call an engineer.

An internal control fault. Reset once. If F0 returns, the control board or gas valve needs testing. Call an engineer.

If the display is blank or the boiler simply is not firing with no code shown, check the thermostat, the programmer and its batteries, and the fused spur. If all of those are right, call us.

EA is the most common Worcester fault code. The boiler is trying to ignite but cannot establish a stable flame. Common causes include gas supply issues, a faulty ignition electrode, or a blocked condensate pipe in winter. Check whether your gas hob works. In freezing weather check the condensate pipe. Reset once only. If EA returns, call an engineer.

If your Worcester shows a low pressure warning, system pressure has dropped below the minimum threshold. Top up via the filling loop to around 1.0 to 1.5 bar when cold. If pressure drops again within days, there may be a leak in the system or a failing expansion vessel. Call an engineer to find the cause.

If your Worcester shows E9, the boiler has overheated and locked out for safety. This can indicate a circulation problem, pump failure, or blocked heat exchanger. Do not keep resetting. Call an engineer to check the system.

On Worcester combi boilers, you may get heating but no hot water, or the reverse. This often points to a diverter valve issue. The diverter valve directs hot water between taps and radiators. When it wears or sticks, hot water delivery becomes unreliable. Call an engineer for diagnosis.