Radiators only heating halfway

E

Eithneangela

Registered User
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939
HELP! In house built 4 years ago, radiators worked fine until now - 2 of them are not heating properly - the bottom half stays cold. What is the best way to bleed them - they are modern rads with a screw thing which when turned, pours out water.
 
Turn heating on. turn off all but the two problem radiators. To turn off a rad, use valve at side.Only one side needs to be turned off.

This could solve it, once two problem rads heat up fully, turn the others back on.
 
you need to bleed your radiator,it sounds like an air lock.
 
Would i be right in saying that usually, If the top part of rad is cold it needs bleeding, if bottom part cold it needs balancing?
 
Where is the valve at the side - is this the thing I need to stick a screwdriver into to try and let the air out - when I do this all that comes out is hot water! Sorry for being so basic but I don't have a clue with this stuff - which is so important at the moment - specially with grandkids coming to stay for Xmas - appreciate your advice on this - will try anything myself before I have to pay for someone to come and wait for the radiators to bleed the air!
 
I had the same problem just now.
As DavyJones suggested, I turned off rads leading to it & left it on.
I also gave it a few gentle taps to vibrate air to top, bled the rads & hey presto, all working again.

Turned back on other rads & all ok now.
 
Stay away from the screwy thing that releases water, this is the vent.

Your radiators are rectangle, on the top corners are a silver blank and a vent. On the bottom corners are the rad valves, one of these will allow you to close or open rad, the other will just spin in your hand as you turn it. These valves are just like taps, anti clockwise to open, clockwise to close.

Turn off all rads except the problem two, this will force pump to only pump to these two rads, this will clear air in line. Assuming air is the problem and not sludge.
 
Many thanks, DavyJones. Tried that, no luck, so it's probably sludge. House was only built in 2005/6 - is it possible for sludge to accumulate in that space of time?
 
You have an air lock in the system, open the top valves and let the air out until the water starts to come out, do this with all your rads until all the air is out. This is a common problem as the sludge creates a gas that will burn as it reacts with the copper. Sludge does not stop the top half from getting hot, my system suffers from this and I clean out the sludge annually and use a retarder.

By a radiator key to open the small square vent plug in the top corner. The one that spins according to Davy Jones is also a valve, you need to pull the cap off it and turn the valve with a spanner if you want to close the radiator off completely by then shutting both valves.
 
Gosh - the terminology has me totally wiped out. All I see is this radiator thing which has two turnable things each side of the bottom. One just keeps turning to no effect, the other seems to manage the amount of heat you get from a radiator. Then, if you move up to the top of the radiator, on the right hand side, there's something which has a place for screw-driver which when you put the screw-driver in, water pours out. On the other side of the top of the radiator is what looks like a silver six-sided thingie! I give up!!
 
I had a similar problem recently in a house <10 years old. Turn off all rads except for the problematic ones, if the problem persists in this small circuit then there is a real issue other than balancing.
Not a bad idea to talk to a neighbour and see if they had any similar sludge problems; in my case there were no problems in the other houses and it was a pump issue...
 
Which is exactly as davy jones described it
 
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