If you don't have any water coming out of a radiator after bleeding, it means you could have something blocking the bleeder valve, the pressure is insufficient in your central
Make sure you've properly bled the entire radiator. If it's still not working, there might be a larger issue with the system, such as a faulty valve, pump, or circulation problem. It's also possible that the thermostat isn't functioning correctly.
What do you do when bleeding radiators but no air or water is coming out? If no water or air comes out when you bleed the radiator, then the valve could be blocked with paint. Close the inlet and outlet valve at each end of the radiator, then remove the screw from the centre of the bleed valve.
1 Answer 1 On a circulating hot water system with bleedable radiators, if you open a bleeder and you don't get air+water or water alone, either the bleeder is clogged or the system pressure is too low to raise the water to that height above the boiler.
Air pockets, inadequate water pressure and faulty radiator valves or TRVs are the three primary reasons why radiators do not work after bleeding.
Usually, it will take between 20 and 30 seconds to effectively bleed a radiator, but it might take up to a full minute in the case of larger radiators. Get help and advice on bleeding radiators with our expert radiator bleeding guide.
This issue could be caused by a faulty thermostat, an obstruction in the radiator, a fan or the water pump has malfunctioned preventing the coolant from flowing and dissipating heat as intended.
Place a bucket or bowl under the TRV at the bottom of your radiator and loosen the TRV at the nut joint with a spanner. Open the bleed valve using the bleed key to remove any air in the system. Sludge and dirty water will begin to drain out. Then, loosen the lockshield valve and repeat.
Bad Water Pump or Thermostat
If the thermostat goes down, the system will not know when to release fluid into the radiator, and if the water pump fails, the system will not have the pressure necessary to circulate the coolant. If either of these things happens, the radiator will not work as designed.
Other than your vehicle running hot, some other signs of a clogged radiator might include radiator hose cracks, low coolant levels, coolant that looks rusty, and leaking coolant.
Keep in mind that you shouldn't get carried away and open your radiator valve entirely or keep it open for too long - too much water will pour out, and your boiler pressure will drop dramatically.
An airlock in your heating system can be removed easily by bleeding the radiators. Doing this will force the airlock out of the system, so you should attempt this task on all your radiators, including the ones that are cold all the way through and cold at the top.
Aside from the danger of working with a radiator that has the heating on, it's also an inefficient bleeding process. If the pump is running when you let out air, this will actually cause the system to draw in more air from elsewhere.
Can you bleed a radiator when the heating is on? No! It's very important to make sure your heating is off, and the radiators are cool before you bleed them. This is because radiators are filled with water and air, which is what escapes when you open the valve (include link to new pressure release guide page).
Fill the unit with water from the mains and switch on the pump. Let the water circulate for 2-3 minutes. Add your cleaning chemical into the powerflushing machine and continue circulating for a further 15 minutes approximately, reversing the flow every 5 minutes or so to improve the initial cleaning process.
You should have some liquid released by the radiator which you can catch in a bowl, at this point you can turn the valve off and turn everything back on. If the banging noise persists, it may be that you need to have your boiler power flushed to ensure all the limescale and grime is removed.
If you have recently bled your radiators, the pressure will drop slightly because you've released the trapped air in the system. This air needs to be replaced with water to get the pressure back up again.
It's advisable to check first whether it's a stuck pin, as these sometimes get stuck in an 'off' position, which needs a quick wiggle to release the pin and allow the water to flow. However, valves can break down, and older radiators may well have degraded thermostatic valves, especially if they're used often.
If your home radiators fail to heat up after bleeding, you should first check for issues with your thermostatic radiator valves, such as a stuck pin on the valve. Alternatively, you can perform a radiator power flush or take steps to ensure your heating system is correctly balanced.
If your radiator is low while the coolant reservoir remains full, a possible explanation is a coolant leak in the cooling system. Inspect the hoses, connections, and radiator for any visible signs of leaks. Additionally, check beneath your vehicle for puddles of coolant, which could indicate a leak.
Burping (so named because of the noise made by the bubbles of coolant exiting the radiator filler neck) is done with the radiator cap removed on cars without a valve. You wait for the car to warm up so the thermostat opens, and then the pressure of the expanding coolant being heated drives the air out.