Why does my boiler make a ticking noise after the burner stops?

A few light ticks after the burner stops can come from hot metal and pipework cooling and contracting. The pump or fan may also continue briefly while residual heat is moved away. A loud, persistent or new ticking sound—especially with faults, leaks or unreliable heat—needs proper diagnosis.

Keep the boiler casing closed. Record the timing and location instead of repeatedly restarting the appliance.

Confirm what has actually stopped

The burner can stop while the pump or fan continues. Manufacturer operating information shows that some boilers run these components briefly after demand ends to dissipate residual heat.

Watch the boiler display from outside. Note when the flame or burner symbol disappears and how long the ticking continues afterwards.

Cooling metal can tick

Boiler panels, flue components and nearby pipes warm at different rates. As they cool, small movements at joints, clips and contact points can create isolated ticks.

A familiar sequence that fades as the appliance cools is different from continuous rapid clicking or a sharp knock that is getting worse.

The sound may come from nearby pipes

Heating pipes can move slightly where they pass through floors, walls or clips. Sound travels along metal, so a tick heard beside the boiler may start elsewhere.

Listen from a normal standing position and note whether the sound follows a particular pipe route. Do not lift floors, bend hot pipes or remove boxing while the system is operating.

Pump overrun changes the sound after shutdown

While a pump moves remaining hot water, pipes and radiators can continue warming or cooling unevenly. A tick that stops when pump overrun ends may be linked to this normal heat movement.

Do not change pump speed or bypass settings. The correct overrun and minimum flow depend on the boiler and installation.

Compare heating and hot-water operation

Does the ticking follow a radiator-heating cycle, a hot tap on a combi, or both? Heating uses much more system pipework, so a noise heard only after central heating can point towards expansion along that route.

Record which radiators were hot and whether the noise is strongest in one room. Do not close every radiator to try to silence it.

A rapid electrical click is different

Repeated fast clicking from the controls, followed by attempts to restart or a fault code, should not be treated as simple cooling metal. Photograph the exact display and stop repeatedly resetting it.

Electrical, ignition and internal control checks belong with a competent engineer. Never remove the casing to locate a relay or spark sound.

Watch for circulation clues

Gurgling, kettling, cold radiator areas, frequent pressure changes or very short burner cycles add useful context. Baxi lists gurgling and kettling among symptoms that can accompany poor system condition or circulation.

These signs do not prove sludge or a faulty part. An engineer should assess the water condition and flow before recommending treatment.

When ticking needs prompt attention

Arrange help if the noise is new and loud, continues long after cooling, becomes rapid or irregular, comes with a burning smell, visible leak, fault code, lockout or loss of heating or hot water.

If you smell gas, call the National Gas Emergency Service on 0800 111 999 and follow its instructions. Do not operate electrical switches or use a flame.

What an engineer may check

An engineer can compare the shutdown sequence with the model instructions, check pump and fan overrun, inspect pipe support and expansion clearance, and assess circulation.

Work inside a gas boiler must be carried out by an appropriately qualified Gas Safe registered engineer.

What to record

Note the boiler make and model, whether heating or hot water was running, the time between burner stop and first tick, how long it lasts and any display message. A short recording can help.

Also mention recent servicing, pipework, decorating or radiator changes. Avoid changing several controls before the visit.

Common questions

Is ticking after shutdown normal?

A few light, fading ticks can be ordinary thermal movement. A changed, persistent or fault-linked sound should be checked.

Can I tighten the boiler casing?

No. The casing forms part of the appliance and should not be removed or adjusted by a householder.

Why does the boiler still sound active?

The burner may be off while the pump or fan completes a normal run-on period.

Related guides: Boiler whooshes at start-up, Boiler runs after the thermostat is turned down and Boiler fails again after reset.