Worcester Boiler Not Firing Up

Start with what the front panel shows

The quickest way to narrow down a Worcester that will not come on is to look at the front before touching anything. Almost every case falls into one of three groups, and each has a different first check.

• Nothing at all: no blue light, no display. The boiler has no electricity, or an internal fuse or board has failed.
• A code, or a flashing blue light: the boiler tried to run and stopped itself. Read the code and see our guide to a Worcester boiler flashing a blue light.
• A normal display with no code, but no flame symbol: the boiler is healthy enough to wait for a demand that never arrives. The timer, thermostat or wireless control is usually the reason.

Blank display: when the boiler is not turning on at all

Find the fused spur that feeds the boiler. It is a switched socket-sized plate, usually beside or below the boiler, often with a small red neon. Make sure the switch is on. Then check the consumer unit for a tripped circuit breaker or RCD.

If the spur is on and the breakers are fine but the boiler is still dead, the fuse in the spur may have blown. It is normally a 3 amp fuse. Only change it with the spur switched off, and only if you are comfortable doing so. A new fuse that blows straight away points to a fault in the boiler or its wiring, so do not keep replacing it.

Past this point the checks are inside the casing: the fuse on the main circuit board, the board itself and the wiring to the controls. That is work for an engineer, not a householder.

A code on screen: the lockouts that stop it lighting

When the boiler has power but refuses to light, the display nearly always tells you why. On current Greenstar models the code appears with a flashing blue light.

• EA 227: the boiler sparked but never sensed a flame. Check another gas appliance works, and in cold weather check the outside condensate pipe for ice.
• Low pressure: the gauge reads well below 1 bar, often under 0.5 bar in the red, and recent models show CE 207. Top up to 1 to 1.5 bar with the system cold, then reset.
• E9: an overheat stat has tripped. One reset is reasonable. If it returns, the pump, a valve or sludge is stopping water moving and it needs an engineer.
• C6: the fan speed is wrong. Resetting will not fix a failing fan.

If you smell gas at any point, open the windows, turn the gas off at the meter if you can do it safely, keep away from switches, then leave the property and call 0800 111 999.

Normal screen, no flame: the heating is not asking

This is the case people most often mistake for a broken boiler. The display is lit, there is no fault, but the boiler never fires for the heating. Test it by running a hot tap; if the taps stay cold as well, work through no hot water from a Worcester boiler instead. On a Greenstar combi, if hot water comes through hot, the burner, gas and ignition all work, and the problem is almost certainly the heating controls.

Check the programmer is in an on period, or switch it to constant for a test. Turn the room thermostat up well above the room temperature. If you have a Worcester wireless thermostat, look for a flat battery or a lost radio link; on Comfort RF controls a lost link shows as A21. Also check the heating temperature knob on the boiler itself has not been turned right down, which switches the heating off on some models.

If the hot tap does not fire the boiler either, and there is still no code, work through our general boiler not firing up checklist, then call someone out.

When it fires, then cuts out

A Worcester that lights for a few seconds or minutes and then goes out has a different set of causes. A partly blocked condensate trap, a weak flame signal from a dirty electrode, low gas pressure at the boiler, or a system that overheats because water is not circulating will all do it. Short firing cycles that end in a lockout are worth a same-day visit in winter, because a partial fault often becomes a full one overnight. There is more on this in our guide to a boiler that keeps turning off.

What an engineer does and what it tends to cost

On a Worcester that will not fire, an engineer reads the stored fault history, then measures gas pressure at the inlet while the boiler tries to light, checks the ignition electrode gap and condition, clears and tests the condensate trap and siphon, and checks the fan and flue. For a dead boiler they test the supply, the board fuse and the board.

Typical market prices including fitting are roughly £80 to £160 for an ignition electrode, £200 to £350 for a fan and £350 to £700 for a main circuit board, depending on the model. A cleared condensate blockage or a controls fix is usually far less.

For Worcester boiler repair the call-out is £60 at any hour, and the repair price is agreed with you on site before any work starts. Gas work is carried out by Gas Safe registered engineers.