It may seem odd to want to stop your boiler from doing what it was designed to do. However, this is a dilemma faced by some homeowners as they seek to find a way of getting their boiler to turn off. This issue can be equally confusing and inconvenient as it could cause your household to become too warm, wasting energy and impacting your energy bills. If you’re currently facing this issue, don’t hesitate to contact us, we could send one of our Gas Safe engineers to your home as soon as possible.

Here are a few of the most common causes of overactive boilers:


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1. Faults with your thermostat

A thermostat fault may be causing your boiler to continue to fire up and stay on. You could attempt to test this issue yourself by turning your thermostat temperature levels down to see if this brings about any change, you could also try to replace the device’s batteries. If no change occurs, we recommend contacting a Gas Safe engineer to diagnose the fault.


2. Programmer defects

Programmers could also be the cause behind your over-functioning boiler system. These control the operations within the boiler and can override the commands sent by the thermostat. To determine whether it is a programmer defect that is causing your issue, your Gas safe engineer will conduct a detailed inspection, turning off the power from the mains and removing the gadget from the wall. They will then check for loose wires and replace the fuse if needed. The engineer may also check the power levels from the programmer to the thermostat by wiring the programmer to another programmable device.


3. Issues with the valves

Valves in the relay connection act as gatekeepers that allow gas to flow to and from the boiler. If these valves are stuck in the ‘on’ position, they can cause boilers to remain on despite contrasting instruction. In some cases, the best solution to this problem is for your engineer to replace the system’s diaphragm or even the whole diverter unit.


4. Issues with your boiler’s wiring

A wiring issue could also be the cause for your boiler not turning off. As is the case with most appliances, tampering with wires can be dangerous. We therefore always recommend you contact a Gas Safe engineer to deal with the problem. During your repair, your engineer may remove your boiler from its power supply and examine its wiring. They may also check the shut-off temperature controls, paying particular attention to the low-temperature switch as this is designed to keep the boiler running if it thinks the water inside isn’t being heated sufficiently; this could therefore be the cause of the fault.


If your boiler comes with a manufacturer-backed warranty, it’s usually prudent for you to contact the manufacturer first when you encounter a problem, so that they can attempt to resolve the issue. Having an independent engineer attempt to fix your boiler could invalidate the warranty, which could potentially mean that you’ll be required to pay for any further issues that would have otherwise been covered.

Any of these issues could be the cause behind your over-active boiler. Here at HomeServe, all of our engineers are Gas Safe registered and trained to deal with a range of boiler issues such as over-functioning boilers. Contact us today and one of our friendly advisors could organise for your boiler to be repaired by a trained engineer at a time that suits you.


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The above information has been provided for information only and is not a substitute for a qualified engineers assessment or diagnosis. Homeserve is not recommending or endorsing any Do it yourself style boiler fixing as a result of the information provided. All heating systems differ in type (fuel and installation) and repairing electric or fuel appliances may pose a significant risk to health and safety where a person is not suitably qualified to undertake such a repair or diagnosis.

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