Do You Bleed Radiators When They Are On or Off?
If your radiators aren't heating up, are gurgling or have cold patches, it's time to bleed them to remove trapped air - and you'll want to turn the heating OFF before you get started!
This safety precaution will protect you from a potentially nasty burn. Even if the radiator isn't hot throughout, the water in your central heating system might be at a temperature that can scald.
As you release air bubbles to get your heating working properly again, there is a strong likelihood of some drips, so leaving the system to cool down before you bleed the radiators is ideal.
How to Bleed a Radiator
The process of bleeding a radiator is simple and won't usually require a professional plumber unless you can't resolve the problem:
- Turn off the heating and wait for the radiators to cool.
- Insert your radiator key into the valve with a cloth or jug underneath.
- Move the valve anti-clockwise until you hear the hiss of air escaping.
- Tighten the value again when water starts to trickle out.
- Repeat on every radiator necessary, from the furthest away from the boiler.
- Turn the heating back on, and see if the radiators are back in action.
If you've followed all these steps, and the heating still doesn't seem to be functioning correctly, it may be that trapped air isn't the cause, and you'll need a plumber to take a look.
Signs That Your Radiator Needs Bleeding
There are many tell-tale signs that you have air in your radiators.
Some get warm intermittently, usually with hot patches at the top or bottom and cold at the other. Radiators with lots of air bubbles might stay cool, even if every other unit is heating up nicely.
You can also hear gurgling and strange noises that indicate the heated water is struggling to get through air pockets.
The valve you turn (or bleeder valve) is usually at the top of the radiator on one of the ends. Look for the round bit with the square knob in the middle - that's your radiator valve.
Standard radiators all have the same type of valve key, or you can pick up spares easily if you don't have one to hand.
If you don't have a radiator key, you can follow the same steps with a flat-headed screwdriver. Place the head of the screwdriver into the notches on the valve, and you'll be able to turn it.
Benefits of Bleeding Your Radiators Regularly
While a cold room isn't great, leaving your heating system for a prolonged time without removing the trapped air can have bigger repercussions and even cause long-term damage.
It's also important to improve energy efficiency since a central heating system working doubly hard to warm each room will use more fuel and cause your utility bills to begin creeping higher.
Periodic maintenance is a great way to prevent wear and tear, and putting your boiler under unnecessary strain could shorten its lifespan.
Over pressurised systems with a build-up of trapped air can cause leakages and water damage, leading to mould and dampness in your home, water stains and even problems with your pipes.
It's also essential to act if you hear any noises from your radiators. If it isn't a simple need to bleed the air pockets, you'll want to get a professional to inspect the system to ensure there isn't anything more serious going on.
Frequently Asked Questions - Do You Bleed Radiators When They Are On or Off?
We've established the need to turn radiators off before you bleed them and leave plenty of time for the water to cool.
Now let's look at some of the common questions about maintaining radiators at home to keep them in great shape.
Should I Release Water When Bleeding a Radiator?
It's normal for a bit of water to escape after all the trapped air has hissed out of your radiator.
As soon as you get water emerging, you'll know that you have dispersed the blockage or bubbles and can close the radiator valve.
Drips are also standard when you turn the valve for the first time - but it shouldn't be a huge gush of water.
Why Do I Keep Needing to Bleed My Radiators?
All radiators need bleeding from time to time - the bubbles in the central heating system are a recurring problem and don't take a huge amount of work to release through the radiator valve.
Often, air enters the system when new water is fed into the expansion tank or during maintenance work.
Therefore, if you've had any servicing or changes to any other part of your central heating or plumbing, it might be worth preemptively checking whether your radiators need bleeding before turning the system back on.
Do I Need to Bleed My Radiators Once a Year?
Yes, regular maintenance will avoid any issues with your radiators and ensure your central heating system is working when you need to turn the heating on.
Most professionals recommend bleeding your radiators every few months, or at least once a year, even if they seem to be working fine.
Can I Bleed Just One Radiator, Or Do I Need to Bleed Them All?
If you have one radiator that seems cold or heating up in patches, you can bleed just that one to remove the excess air, turning the central heating back on once all the air has been released.
However, it's worth doing all of the radiators simultaneously while you've got the valve key to hand and a jug to catch any drips, so you don't need to turn the heating off again in a few weeks.
The best way to check which radiators aren't working properly is to turn the heating on first, give it time to warm up, and then check each radiator carefully (being conscious that they may be hot to the touch).
Any units with cold spots need bleeding.
References:
- https://www.homeserve.com/uk/living/heating-and-cooling/how-to-bleed-a-radiator/
- https://sse.co.uk/help/home-services/bleeding-a-radiator
- https://www.bestheating.com/info/how-to-bleed-a-radiator/
- https://www.eonenergy.com/boilers/heating-hub/issues/how-to-bleed-a-radiator.html
By Johnny Fuller
Home Improvement editor at NWrenovations.com
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