If the pin has stuck, you can take the valve head off and tap the centre pin very gently, which will release the washer, and the valve should work. It would not be advisable within any room to completely close the valve. Closing the valve fully is likely to encourage dampness into the room and, therefore, create mould, discolouration, and other health risks.
Heating, Hot water and Radiators
If you find yourself without heating and hot water, here are some steps you can take:
Check the electrical power and gas supply: If your other gas and electrical appliances are working but your boiler isn’t, check your fuse box to make sure a switch hasn’t tripped and cut the power to your system.
Pilot light: If your permanent pilot light has gone out, try relighting it following your manufacturer’s instructions. If it keeps blowing out, it’ll need to be checked by an engineer. Most modern boilers have a pilot light that only ignites when there is a call for heat. So asserting there is a gas supply is both time and money saving, so check you other gas appliances are working and check the gas meter has credit and the gas supply valve is open.
Water pressure: For your boiler to work at its best, your ideal water pressure should be between 1 and 1.5 bar. So, if the pressure’s not quite high enough, adjust it carefully using the filling loop. You can get further assistance by using a quick internet search; 'How to add water pressure to my boiler ( insert make and model of boiler here)'. There are many videos availble to assist.
Thermostat: If your temperature is set below 21℃ your boiler might not come on at all, so you’ll need to increase it. Also ascertain the thermostat batteries are not drained (if applicable, as a call out charged for a boiler engineer to replace a battery can be VERY expensive)
Timer: Power cuts and accidental knocks can throw your boiler’s timer out, so double check that yours is still set correctly and adjust it if not.
Water tank or cylinder: If so the problem might lie with the thermostat/programmer on the tank or cylinder itself.
Boiler reset: Some boilers need resetting occasionally for all sorts of reasons; not all of them serious. So, locate your reset button and try resetting it according to the manufacturer’s instructions.
Frozen pipe: If it’s very chilly outside, your boiler’s condensate pipe might have frozen. You can try to thaw it using hot (but not boiling) water or a hot water bottle. Information here
Fault Codes: Most modern boilers have a digital display and if there has been a fault detected then this will usually flash up on the display. A simple google search using the make and model of the boiler may offer a quick solution.
If you’ve tried all of the above and there’s still no hot water coming from your taps, try switching the boiler off at the mains for a few seconds, before turning it back on again1. If you’ve tried all of the above and you still have no hot water, it’s time for a Gas Safe engineer to take a look1.
What you need to begin when bleeding a radiator
Before you get started, you’ll need to gather the following:
A radiator key – you can get one from most DIY stores
A cloth, or towel to catch any drips and protect your carpet from dirty water
Modern radiators can usually be bled without a key. But if yours can’t be, don’t worry, you can always use a screwdriver as an alternative.
Now take a look at the radiator’s bleed valve, which has a square screw or bolt. You’ll find it at the top of the radiator, either on the side or at the back. If there’s a small slit in the middle, you could use a flathead screwdriver to open it.
Only use a flathead, though, not a crosshead screwdriver – as this can damage the valve. And definitely don’t use pliers, for the same reason.
Which radiator to bleed first?
Generally speaking, you should bleed the radiator that’s furthest away from your boiler first. If you live in a 2-storey (or more) home, then this will probably be downstairs.
Work your way around your home, until you reach the radiator closest to your boiler.
7 easy steps to bleed a radiator
- Start by turning the heating off, and most importantly, wait for the system to cool down. This will save you from burning yourself if water escapes.
- Next, find the bleed valve.
- Then, put your cloth under the valve, ready to catch any water that escapes.
- Fit the radiator bleed key (or your flat head screwdriver, if that works) in the screw. Turn it anti-clockwise about a quarter of a turn, or until you hear a hissing noise (that’s the air coming out). You might also get a few drops of water, so have a cloth to hand!
- Wait until all the air has escaped. You’ll know when that happens, because water will start seeping out instead.
- Next, tighten the valve again. It needs to be tight enough to stop air getting in, but not so tight that you can’t open it the next time.
- Turn the heating back on and your radiator should soon be working fine.
Just give your boiler pressure a quick check too, and you’re good to go!
it’s a good idea to bleed all your radiators at the same time.
Top tip: valve fall-out
When you’re bleeding your radiator, don’t turn the screw on the bleed valve more than one-and-a-half turns, or it could come out completely.
If that happens and you can’t get it back in right away, don’t panic. Turn the radiator valves off via the screw or dial valve at the bottom. That should stop more water from getting in while you re-attach the screw.
How to bleed radiators with a combi boiler
For combi boilers, and boiler systems that are pressurised, there’s one extra step. After you’ve released the air, check the pressure gauge on the front of your boiler. Usually these should be between 1 and 1.5 bars. But check your boiler manual to be sure.
With these boilers, you can actually let out too much air, making the pressure too low. If that happens, it’s usually just a question of turning a valve to let in some more water – but again, check your boiler manual to find out the process for your model.
Can’t find the boiler manual?
To be honest, who can? If this applies to you, check the make and model on your boiler itself. Once you have this info, you can head online to the manufacturer’s website where you’ll be able to download a new manual.
Why do I need to balance my heating system?
In an unbalanced system the temperature your home reaches may not match the one you set. For example, when you set the thermostat to 20°C you would expect the whole home to heat to, and stay at, 20ºC.
However, with an unbalanced system, the upstairs might actually reach 23°C, while the downstairs remains relatively cool at 17°C. You may then be tempted to turn up the thermostat (in this example to 23°C), which will create a comfortable temperature of 20°C downstairs, but superheat the upstairs to 26°C.
The Energy Saving Trust estimates that turning up the thermostat by just one degree costs an additional £75 a year in heating costs. So turning up the thermostat will just increase your bills, whereas getting your radiator rebalanced will save you money in the long run.
The tell tale signs of a poorly balanced system include some radiators heating up much faster, or getting much hotter, than others in your home.
Another clear sign is if certain parts of your house (such as upstairs) get uncomfortably hot, while other parts stay cool.
How to balance your heating system
- Turn off the boiler for at least two hours for the system to cool off.
- Bleed all radiators and ascertain the boiler pressure is around 1.5 bar (see above)
- Turn off all radiators at the valve (some radiators have thermostatic valves as photo above, others have a standard valve)
- Most radiators have a combination of both, but always turn off the standard valve. The thermostatic valve can then be used to control room temperatures during every day use.
- Some times the white cap is missing and you will need to use a pair of plyers to close the valve (right= close. left=open).
- Apart from the bathroom (or the radiator closest the bathroom); Do not turn this radiator off.
- Turn on the boiler from cold.
- Then working back towards the boiler from the bathroom radiator or the one which you have left open -open the thermostatic valve and then adjust the smaller radiator valve towards open (Left = open) as this valve controls the flow. You need to find the balance where the radiator is just getting hot on all radiators. You will feel the supply pipe getting hot first then you can tweak the valve until the point the radiator starts to heat. If the heat enters the radiator with only one valve open the turn backoff and start with the opposite end i.e. open the other end fully then tweak the end where the heat enters first.
- work through all radiators to get them balanced.
- Top Tip; Sometimes just closing all the valves on the ground floor radiators will force the heat to the first floor, then you may be able just to tweak the ground floor valves to allow the heat back.
Why is my system unbalanced?
- Sludge and debris Old systems may be clogged up, causing blockages in some radiators, meaning they take longer to heat up.
- Redecorating When radiators are removed and replaced, perhaps during decorating, this can impact the balance of the heating system.
- Misuse of Thermostatic Radiator Valves (TRVs) If TRVs have been fitted to radiators around your home, and not adjusted correctly, this can lead to system-balancing issues.
It's easy to tell if you have inadvertently unbalanced your own heating system with TRVs:
- Turn all radiator thermostats to 0.
- Turn the central heating off and wait for at least two hours for the system to completely cool off.
- Starting from the radiator furthest from the heating source if you have a combi boiler, or furthest from the water pump (usually found in the airing cupboard next to the hot water cylinder) if you have a heat-only boiler, turn all thermostats to 2.
- Starting from the radiator furthest from the heating source, check if all radiators get hot evenly across the radiators at the same rate.
If they don’t, the system is not balanced properly and we would recommend that you follow the action already detailed above.
WHY DO THERMOSTATIC RADIATOR VALVES STICK?
The top of the valve consists of a wax capsule that is heat sensitive and, therefore, expands and contracts. As it swells and shrinks, it pushes down on a pin within the lower section of the valve body. The pin pushes down on the washer that regulates how much water flows through the valve and into the radiator.
In the summertime, when your central heating is turned off, the valve head or the wax capsule will become hot through the increased summer temperatures and will push down on the pin. The consistent warmer summer temperatures often mean the pin remains in the same position for the entire summer. When winter comes, it is not uncommon for the washer to be stuck within the valve, preventing the radiator heating up.
To prevent the TRV from sticking, the best thing to do at the end of the heating season would be to open the valve so that it is fully open. You can then turn the heating system off.
HOW TO FIX A STUCK THERMOSTATIC VALVE
If the pin has stuck, you can take the valve head off and tap the centre pin very gently, which will release the washer, and the valve should work. It would not be advisable within any room to completely close the valve. Closing the valve fully is likely to encourage dampness into the room and, therefore, create mould, discolouration, and other health risks.
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