When I bleed my radiator, Air starts coming out then stops.?

Question

My riadiator will not bleed. Air starts to come out when I turn the bleed key. But after a few seconds stops. No water comes out. I have checked the header tank and there is water in it.

Answer 1

close the larger valve (flow - the one you can turn on/off), bleed rad, then open valve (do to all rads 1st), let system run for 5 mins, repeat process.

this will force air into rads, and should clear system of air. hope this helps

if this doeant work, run system with flow valves closed, this will allow air into the return pipe (into rad), then bleed rads whilst running.

Answer 2

Usually if the radiator is upstairs then turn the heating off IE ( switch the pump off ) and vent the radiator. On older systems the pump was installed on the return the theory was that it would run that much cooler the problem that usually occurred was that air was sucked in because the system was running under negative pressure, this is why the brains of Britain think that bleeding a radiator will solve all your problems really they are just after the 2 points, god help the doctors if they ever get pregnant CANT BE DOC. MUST BE AIR IN THE SYSTEM. LOL If the rad still wont vent close the valves ( both ) off, remove the vent screw and clear the hole out with a wire or needle, replace the vent screw and turn the valves on then re- vent the rad.
Turning the valves off prevents dirty black water squirting up the walls and if you drop the vent screw as you do, you aren't stuck there with one finger over the vent hole shouting HELP.
Another little tip put a bit of paper in the vent key as the vent screw can disappear up the vent key socket and then you can't get it to start in the threads. Also do it when the system is cold not important but it stops you getting burnt with hot water.

Been there got the tea shirt

Heating engineer 40yrs +

Answer 3

Don't hire a plumber...it will cost you a fortune....honestly. It is a very simple job and I've done it many times myself. You can't go wrong : 1. Buy a radiator key from DIY store. 2. The bolt on the radiator can be located at the bottom of it on one side. Have a bowl just underneath the bolt hole. 3. Use the radiator key and turn 3 or 4 times, slowly till you hear the air hissing out. When water starts to come (don't worry it's not like a tidal wave), turn the bolt back with key. Hey presto!! Do the same thing for all the radiators. I promise you....it is soooo easy. (Plumber £30 call out then add another £40 to £50 on top.)

Answer 4

Are you sure that air is coming out. The sound of air going in, is just the same. If the radiator is fitted in the pipework near the suction side of the pump, then it may be operating under a slight negative pressure. This will cause air to be sucked in. The hiss you hear will sound just like air coming out. Hold a small piece of tissue paper over the bleed hole to check the direction of air flow.

Try bleeding with the pump turned off. If it then bleeds ok, then your pump (which is likely a three speed) is set at too high a speed. Set it down one position.

Answer 5

Make sure that the radiator valves are BOTH open and the heating on allowing flow of water into the radiator. Then have patience - it will flow with water, unless there is a blockage in the pipework.

Answer 6

make sure your valves are open on both ends. This needs to be done to bleed your rads

Answer 7

turn your radiator on before you bled then.and if your radiator is block.black water will come out first.then when clear water come out.you know that your radiator is clear of trap air and dirt.

Answer 8

I had probz with 1 rad similar to this, i turned the heating on then bled it.