If radiators begin to fade and not heat properly, bleeding should be your first move, unless there’s an obvious fault with the boiler. Bleeding your radiators is a simple process that involves releasing the trapped air from the system so that the water can flow freely again.
Here at SES Home Service, we want to make sure Clik2Fix is making your home repairs as stress free as possible. That’s why below we’ve created a guide to help you know when to bleed your radiator as well as a step-by-step process that you can carry out yourself.
When should you bleed your radiator(s)
There are a few tell-tale signs that your radiator(s) may need bleeding:
Cold Spots: You should check your radiator(s) every few months to ensure that they are working as efficiently as possible. If you notice that your radiator(s) have cold spots it may be a sign that air has got trapped within them. This is the most common indicator that your radiator(s) need bleeding.
Mould and Damp Appearing: If mould and damp begin appearing in one of your rooms it could be a sign one of your rooms is colder than the rest. This is oftentimes caused by a radiator working inefficiently, potentially from trapped air.
Rattling and Gurgling from Radiator(s): When air gets trapped within your central heating system it can cause quite the ruckus. If you hear rattling and gurgling from your radiator(s) they may be working inefficiently and costing you more on your energy bills. Bleeding them could save you from annoying noises and save you money.
What you need to bleed your radiator
- A towel or cloth – to soak up any water from your radiator and to protect your floor.
- Radiator key – to open your radiator valve to let the trapped air escape.
- A bucket or bowl – to collect any excess water from your radiator.
- Protective clothing – if available use gloves and glasses to protect you from any spills or steam.
Bleeding a Radiator - Step by Step
- Identify which of your radiator(s) need bleeding: make sure your heating is on and check all your radiators for cold spots. If there are multiple radiators with cold spots, make sure to check which ones are furthest away from your boiler.
- Turn off your heating and wait for your radiators to cool down: Warning! you CAN’T bleed radiators when your heating is on, and you should always check this before doing so. If you try to bleed your radiators when your heating is on you risk causing serious harm or damage to you and your room.
- Place a towel and bowl under the radiator valve: Before opening the radiator valve make sure that you have prepared for potential spills or leaks. This way you can avoid unnecessary damage to your floor and room.
- Open the radiator valve slowly: With your radiator key open the radiator valve slowly. If there is trapped air within the radiator you will hear hissing, keep the valve open until the hissing stops. Once the hissing stops, close the valve. If water starts spurting out you’ve opened the valve too far.
- Check that the radiator valve is tightly closed: This prevents any future leaks and helps you to ensure your central heating system is working efficiently.
- Carry this process out on any other radiators: For the best results carry this process out on all your radiators.
- Check the pressure of your boiler: After releasing air from your central heating system your boilers’ pressure may have changed. It should be between 1 and 2 bars. If it is too low or high than this, you will have to repressurise your system [future blog].
For more home repair and maintenance tips, visit our blog here.
We are one call away whenever you need us – call 0208 722 7072 and one of our knowledgeable team will assist you in booking an appointment to keep your home in tip-top condition.
Let’s discuss a leaky boiler next.
How To Fix A Leaking Boiler
A leaking boiler is perhaps one of the more alarming boiler issues you might encounter - but don’t panic! Here's how to fix one.
Boilers are durable, robust workhorses that we can usually rely on to heat our homes year after a year.
After years of humble service, boilers will likely show evidence of wear and tear and their performance will eventually falter.
While any boiler problem is likely to cause some alarm, many issues are fairly benign and can be sorted out with a minimum of fuss. On other occasions, it’s worth getting professional advice as soon as possible.
A leaking boiler is perhaps one of the more alarming issues you might encounter - but don’t panic! Not all leaks are the sign of a major fault, but time is of the essence - don’t ignore a small leak and let it develop into a bigger one!
This is a guide to leaking boilers and how to fix them.
How do I know if my boiler is leaking water?
The telltale signs of a boiler leak are:
- Drips coming from the boiler itself, including the cover.
- Drips emanating from nearby pipework
- Unexplained damp or moisture near the boiler
- Rapidly corroding pipes in and around the boiler
You’re probably most likely to find drips coming from the pipework at the top or bottom of the boiler, depending on what boiler it is and where it’s installed.
Is a leaking boiler an emergency?
A water leak isn’t an emergency in the same sense as a gas leak, unless the water is pouring out of your boiler!
Whether or not a leaking boiler is dangerous or not depends on the boiler itself. If it’s a newer combi or system boiler and the water leaks through the electronics inside the boiler, the water may cause an electrical short. This could be dangerous, though boilers are designed to prevent anything like this from happening.
If you spot even a small leak in/from your boiler, it’s wise to shut the boiler off immediately. If you have a newer boiler that contains electrical components, be careful when touching it if it’s wet. Shut off the electricity at the switch or breaker if possible.
Can I use my boiler if it's leaking?
While using an older conventional boiler while it’s leaking a little isn’t dangerous, the problem won’t go away and will eventually lead to much greater problems down the line, such as widespread corrosion.
If you have a newer combi or system boiler with electric components, then you should shut your boiler’s power off at the mains and stop using it immediately.
Regardless of what boiler you have, if the leak is serious (e.g. the water is gushing out and not just dripping), then shut off your water at the stopcock or the stop valve in the road.
Thames Water has a guide on finding and using your outdoor stop valve here.
Does a leaking boiler cause low pressure?
If you have a modern boiler (e.g. a combi or system boiler), then a leak anywhere in the system will cause low boiler pressure. You’ll be able to identify low pressure from the pressure gauge on the boiler itself. Most boilers require a pressure of 1 to 2 bar.
If you have a conventional or traditional gravity-fed system, then a small leak will still impact your central heating performance, but not to the same extent.
How dangerous is a leaking boiler?
A boiler leaking a small quantity of water is still a high priority fault, but not an emergency. The only exception is if the boiler is a combi or system boiler and the water leaks through the main electrical components. In this case, short-circuiting of the electrical components is possible.
Above: Boilers with electrical components are vulnerable to water damage
Modern boilers should automatically shut off if they detect a leak or other issue, though. Here are some leaking boiler error codes to look out for:
Boiler Brand Possible error codes:
- Worcester Bosch - A1, E9, CE207, HO7
- Vaillant - F.22, F.24, F.13, F.73, S.41, S.53
- Ideal - F1, L1, FD
- Baxi - 117, 118, 125, E78, H.02 – 06
In any case, it’s sensible to isolate a leaking boiler from the electricity. To safely isolate a leaking boiler, switch the entire off at the mains.
You should be able to find a breaker switch. Failing this, check your main breakers. If you still can’t find how to switch it off, switch off the main switch and call one of Gas Safe engineers to fix the problem as soon as possible.
Why is my boiler leaking water?
Boilers can leak for several reasons. The source of the leak will provide some clues, but can often be difficult to identify.
1: Corrosion in pipework
If the leak emanates from the pipes under on top of your boiler, it might be caused by corroded pipework. Leaks tend to start small and develop over time.
Above: Most leaks come from underneath a boiler
Small leaks (also called pinhole leaks) can result from a build-up of sludge and grime inside the pipe. These are relatively easy to fix if the pipe can be isolated and repaired. However, it’ll be much harder to repair if the corrosion spreads to other components.
2: Corrosion inside boiler
If corrosion penetrates the boiler itself, it can affect practically every component inside. Removing the boiler’s case will reveal whether or not there’s a leak inside, and whether it’s causing any corrosion.
While Gas Safe does say it’s safe to remove the case of most boilers, so long as you follow the manufacturer’s guidelines and isolate the electricity, it’s advisable to call our Gas Safe engineers if you’re not confident.
3: Broken or leaking seals
Seals are there to prevent leaks, so if they fail, leaking is inevitable! Virtually any connection between two pipes or components will have a seal. Corrosion or high boiler pressure may cause the seals to fail over time.
4: Loose joints
Similarly to the above, loose joints can cause leaks.
Joints may loosen due to vibrations in and around the boiler, especially if it’s placed near a washing machine or other electrical appliance. Corrosion may also seep through the joints and provide a means for water to escape.
5: High pressure
Combi or system boilers (and some older boilers) will come equipped with a pressure gauge. Boilers commonly operate between 1 and 2 bar, which will be marked by a green zone on the gauge. If the boiler pressure is too high, your system becomes more vulnerable to leaks.
Leaks can quickly develop in a system operating above its recommended pressure range.
Excessive boiler pressure is often caused by a build-up of air in the system or an airlock.
6: Poor installation or repairs
Leaks may result from shoddy boiler installation or repairs. If your boiler has been serviced, replaced or repaired recently, and you later find a leak, you should call the installer as soon as possible.
Often it’s just a case of re-tightening a joint that has shaken loose during standard operation.
7: Wear and tear
Boilers wear over time. Leaks resulting from general wear and tear might take years to develop, but boilers older than 15 to 20 years likely need more regular and intensive servicing to prevent leaks and other issues from developing.
Corrosion is a common issue, especially when the boiler is installed in a damp environment already, like a garage.
8: High temperature
One of the valves installed in a boiler is the temperature control valve (TCV). If the TCV wears, corrodes or develops some other fault, it might leak water while simultaneously failing to regulate the system’s water temperature.
This is one of the more serious faults, as it’ll cause your hot water to approach scalding or even boiling temperatures. This can include water within the hot water cylinder, read our guide for more information.
How to fix a leaking boiler?
In almost all of these situations, you’ll need to contact a Gas Safe engineer to properly diagnose the problem, with a few exceptions:
If the leak is coming from a join or seal
If you can see that the leak is coming from a joint or seal, then you can try tightening the joint with a spanner yourself. Resealing the joint with plumbers tape is also an option, but you’ll have to isolate the section from the water supply or drain the system first.
Above: Sometimes you’ll just need to tighten the leaking pipe
If you’ve recently depressurised your system
If you’ve recently depressurised your boiler or fiddled with the filling loop tap underneath the boiler, ensure the black taps on the loop are closed properly. If they aren’t closed properly, your boiler pressure will remain too high.
Above: Boiler filling loop
If your boiler pressure is too high
If your boiler pressure is consistently too high, start by bleeding your radiators. You’ll need to move through your home systematically, bleeding each radiator at a time. It shouldn’t take much longer than half an hour or so. If you notice any leaking from your radiator, read our guide here.
Above: Bleeding radiators can fix a number of central heating issues
How to prevent a boiler leakage
A well-fitted modern boiler is extremely unlikely to develop leaks for many years, providing it’s well-serviced. The older the boiler and central heating system in general, the more likely leaks become.
1: Service your boiler
Servicing your boiler is the best way to keep it working smoothly year in, year out. The standard advice is to service a boiler every year, before winter - so around late summer.
The Gas Safe engineer will also be able to check for faults and proactively replace worn parts. The older your boiler is, the more important servicing is. But, any and all boilers benefit from yearly servicing.
2: Keeping an eye on corrosion
Corrosion is the primary cause of tiny leaks that gradually worsen. Keep an eye on your boiler and its surrounding pipes - you should address any tiny leaks accompanied by corrosion as soon as possible before the issue spreads.
3: System flushing and magnetic filters
An corrosion-ridden system can be cleaned with a chemical flush. Fitting magnetic filters to the boiler also extends its life when the rest of the system is quite old.
Summary: Boiler Leaking Water – How To Fix A Leaking Boiler
Leaking boilers are generally not an emergency, unless the water is leaking into internal electrical components. In this situation, most modern boilers should switch off automatically, but you can’t take that for granted.
If you suspect that water has leaked inside your boiler’s electronics, shut it down at the mains breaker.
In most situations, a leaking boiler warrants professional attention - a Gas Safe engineer will be able to diagnose and repair the fault safely.
Even small leaks shouldn’t be ignored, as they’re bound to get worse over time. Call one of our Boiler service engineers if you are not sure. If you are covered by our boiler and heating insurance contact us to have an engineer investigate your issue.
Now, what about a noisy boiler?
Have a Noisy Boiler? Here's How to Fix It
Do you have a noisy boiler? Are you struggling to fix it, discover your options with our guide on noisy boilers.
First and foremost, heating systems are full of pipes and components that expand and contract naturally with use.
As such, some level of audible noise coming from your pipes, boiler, radiators, and the hot water tank is normal. However, keeping a close eye (or ear) on the noises emanating from your heating system will help you diagnose potential faults, and stop minor issues before they become more serious.
Noises coming directly from your boiler are a greater cause for concern than noises coming from elsewhere, which we’ll discuss shortly.
Here’s how to diagnose and fix a noisy boiler.
The top causes of a noisy boiler
Noisy boilers and other noisy central heating components can be caused by a range of issues.
Some of the main causes of a noisy boiler are:
- Limescale build-up, especially around the heat exchange
- Airlock near the boiler
- Pump issues
- Faulty thermostat
- Low water pressure or insufficient water
- Other internal mechanical or electrical boiler issues
Where the noise is coming from
To diagnose the cause of the noise, you’ll need to pinpoint the whereabouts of the noise itself. The noise may emanate from:
- Your boiler
- The pipes surrounding the boiler
- The hot water tank (if you have one)
- Pipes under the floorboards or in the walls
- The radiator
- The pump, typically mounted near the hot water tank in a conventional heating system
If the noise comes from your pipes or radiators but disappears after your central heating system has been switched on, it’s probably nothing to worry about.
However, if the noise persists, doesn’t go away, or becomes worse over time, it’s time to take notice.
Noises coming from plumbing pipes aren’t usually anything to worry about unless they’re very loud or persistent.
What type of noise is the boiler making?
To fix a noisy boiler, pay attention to the type of noise the boiler is making. Here are the noises you’re most likely to hear:
Boilers often vibrate slightly during regular use. If the vibration seems too loud, ensure the boiler is properly secured to the fittings.
Part of it may be vibrating against the wall or another piece of metal. The same applies to any vibrating pipes - they may need to be padded to prevent contact with other surfaces.
Loud banging noises
Banging noises or radiator rattling noises are probably the most common, and can be caused by several issues. Firstly, check whether the banging noise is coming from:
- The boiler itself
- The radiators
- The pipes
If the banging is coming from the boiler, this may signal limescale buildup around the heat exchanger. This may also affect your central heating’s overall performance.
To fix this, you’ll probably need to disassemble the boiler, which is illegal unless you’re a Gas Safe registered engineer.
Another possibility is that your pump is seized, or your water pressure is too low. Combi and system boilers don’t have external pumps, as they take water directly from the mains.
If you have a combi or system boiler, check your boiler’s pressure gauge to ensure it’s between 1 and 2 bar (there will be a green zone marked). If it’s fallen below this, it’s worth checking your system for leaks in either the radiator or the pipes.
If you have an external pump, usually mounted in the airing cupboard, that might have seized.
You’ll probably find this in your airing cupboard.
Sometimes, you can tap the pump with a spanner to get it working again. You can also bleed the pump similarly to a radiator. Otherwise, it might be faulty and in need of replacement.
If the banging comes from your radiators, consider bleeding them.
Banging may also accompany whistling or kettling noises, which are covered below.
Kettling or whistling noises
If your boiler is whistling or sounds like a kettling, i.e. ‘kettling’, then this might signal overheating or limescale build-up. If you have a combi or system boiler, it should have a thermometer on the front that indicates the temperature.
If the gauge is in the red, shut your boiler down and call a Gas Safe engineer. It may be that the boiler’s overheating shut-off has failed.
Whistling noises produced by radiators are often remedied by bleeding the radiators.
Heating systems gurgle somewhat as standard. However, intense gurgling that seems to be getting worse often indicates a wider issue. One of the most common culprits is an airlock in the pipes.
There are a few DIY fixes for airlocks, including flushing and refilling the system, but it’s often advantageous to seek advice if your boiler and/or nearby components are gurgling a lot.
Banging or tapping pipes
Pipes expand and contract with use, producing banging or tapping sounds. If these occur when you switch your heating on or off but subside after, it’s probably nothing to worry about.
Loud or persistent banging pipes may be a sign of trapped air, an airlock, or too high or too low water pressure.
To remedy banging pipes, you can try flushing the entire system, like fixing a gurgling noise.
How to fix your noisy boiler
If you’re sure the noise is emanating from within the boiler itself, you should contact SES Home Services. Boilers will make some noise, but they should run pretty quietly.
If the sound is a whistling or kettling sound and is accompanied by overly hot water, take action immediately - this may signal an overheating issue.
Check your boiler for error codes. Modern boilers are extremely unlikely to fall victim to serious faults without shutting down and displaying a code.
Example boiler error code
1: Check if the system needs bleeding
Banging, gurgling and similar noises may signal excess air in the system. If the radiators are the source of the noise, bleed them in sequence. The pump may also require bleeding. If that fails, consider emptying and refilling the system.
2: Check the water pressure
Both low and high water pressure is linked to a noisy central heating system. Checking water pressure on combi or system boilers is easy - look at the pressure gauge on the front of the boiler. Conventional systems don’t usually have a pressure gauge, as they’re gravity-fed.
Low pressure might signal an airlock, limescale, sludge or a leak. Excessively high pressure is less likely, but may result from a faulty pressure relief valve (PRV).
3: Check for frozen pipes
When boiler issues present with extremely cold weather, it’s always worth checking for frozen pipes. The pipe most likely to freeze is the condensate pipe, which runs on the external wall at the rear of a condensing boiler.
Summary: Why is My Boiler Noisy And How to Fix It?
Firstly, any loud noises produced by the boiler itself shouldn’t be ignored - call a heating engineer as soon as possible.
Most central heating noises are relatively easy to diagnose and fix. Air in the system is a common issue, as is a build-up of limescale or sludge. If you have a conventional heating system with a hot water tank, check the external heating pump.
If you’re unsure of what’s causing the noise or how to fix it, call SES Home Services today.
Read our other guides on radiators
What To Do When Your Central Heating Won't Turn Off
Most heating issues are concerned with the heating not turning off, but you might find that your heating doesn’t actually want to turn off.
Here’s a curious heating issue that some people encounter - your heating turns on but doesn’t turn off.
Most heating issues are concerned with the heating not turning off, but you might find that your heating doesn’t actually want to turn off.
If your heating doesn’t turn off, you’re more likely dealing with an electrical or settings fault rather than a mechanical one.
Here’s what to do if your heating won’t turn off.
Why won't your central heating turn off?
If your central heating doesn’t turn off in the usual fashion, bear in mind that you can manually shut off the power to the boiler if you need to.
Many modern combi and system boilers have a power switch that you can simply switch off to turn off the heating. You can shut off individual radiators in a conventional system by turning them off at the TRV and lockshield valves.
If you need to shut your central heating down in an emergency, you can shut off the gas supply to the boiler and house. If you smell gas and suspect a severe fault, phone your energy supplier’s emergency line as soon as possible.
Here are the four main reasons why your heating doesn’t turn off:
1: The Thermostat Is Faulty
The thermostat’s job is to relay your home’s air temperature to the boiler. Older thermostats take the form of a small rotary dial, whereas newer ones are LCD or touchscreen.
Above: Conventional rotary thermostat.
Thermostats are quite simple. You set the desired temperature on the thermostat, your home heats up, and when the target temperature is obtained, the heating switches off.
However, settings issues and faults can prevent the thermostat from signalling the boiler to turn off. If the thermostat isn’t working correctly, the boiler may not switch off.
Turn your thermostat to zero before you try anything else and wait to see if that turns your heating off. If that fails, check the settings carefully.
‘Finger faults’ are common with modern touchscreen thermostats and programmers, which have many different settings and options. If you have a smart home-enabled thermostat, check the settings in your smartphone app.
Above: Smart thermostat
- Firstly, try changing the batteries. If that has no effect, the thermostat might be suffering from faulty wiring or a broken sensor.
- If it’s a newer digital thermostat, reset it and start over again.
- If you’ve installed it recently, run through the setup process again.
- Lastly, if your thermostat is smart home-enabled, ensure that none of your devices is keeping your heating on.
2: Programmer or Timer Defects
The boiler programmer or timer may also be faulty. Bear in mind that the programmer and thermostat may be separate or part of the same unit.
Firstly, check the programmer or timer unit to ensure the settings are correct. The time should match the actual time. You can also try resetting the entire unit if possible.
If everything looks in order, there may be an issue with the main circuit board (MCB), meaning the unit is failing to instruct the boiler to switch off.
A heating engineer will be able to test and bypass the programmer/timer/thermostats to find out which one is at fault.
- The programmer/timer may be the same unit or might be separate.
- Ensure all settings are correct and that the time is right.
- Try resetting the unit and dialling in the settings again.
- Our heating engineers should be able to test and bypass the unit(s) to see where the issue is.
3: Issues with the valves
Boilers contain motorised valves that control hot water flow to the heating system. The boiler communicates with the valves and tells them to close when the heating is switched off.
Above: 3-way motorised valve
However, if the valves fail, the heating won’t switch off when instructed to do so.
Motorised valves can either break or become locked in the ‘open’ position. A heating engineer should be able to quickly tell whether the valve is the issue. Replacing the valve or its components should fix the issue.
- Boilers contain motorised valves that open/close the flow of hot water.
- These valves can break or become seized.
- Replacing the valves or system diaphragm should fix the problem.
- This is a job for one of our heating engineers.
4: Issues with boiler wiring
Rarely, the boiler’s own internal circuitry can fail. For example, if water enters the system via a leak, it might short out the electrics and prevent the boiler from shutting off the hot water supply.
If this or something similar happens, your boiler will likely display an error code. Check this error code against the manual to get an idea of the fault. If you suspect an electrical issue, you’ll need to call a heating engineer.
- Rarely, the boiler’s internal wiring may fail.
- Leaks or short circuits could be the issue.
- Check for boiler error codes.
- Call one of our heating engineers.
How to Turn Your Heating Off
Turning off modern boilers is simple; simply locate the power switch and turn it off. In addition, you can often shut off the heating and hot water separately. You can also turn the thermostat down, or turn it all the way to zero to prevent the boiler from heating.
Above: You can turn the water and heating dials to zero on this boiler.
The procedure for older boilers varies, but most have a dial or switch you can turn off, or turn down to zero. If you’re turning off a gas boiler with a separate hot water tank, it’s best to locate the supply valve on the pipe from the water tank itself and turn that off too.
If you need to turn off your boiler in an emergency, you can shut off the gas at the boiler or the gas isolation valve.
You can also shut off individual radiators at the TRV and lockshield valves.
Summary: My heating won't turn off
If your heating doesn’t turn off, the issue probably lies with the programmer/timer/thermostat, which may be different units or part of the same unit. If you have a complex modern programmer, check the settings thoroughly.
Reset if necessary - ‘turning it off and on again’ can work as well here as it does in other situations!
Never start disassembling the boiler or other essential components without advice. If you’re unsure of what to do, contact our heating engineers.
If the smell of gas accompanies a boiler fault, call your energy supplier’s emergency line. If this doesn't help with your problem, discover the 10 most common boiler problems.
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