Rads hot at top, cold at bottom. Help and information on all topics relating to your central heating, air conditioning and ventilation issues.

[Apip]

Morning all,

I have a couple of problems I hope some one may help with.

I've built an extension on to the back of the house at the end of last year and we put in a new rad, branching of from the nearest one, i the dinning room. Its around 4 meters away.

When the rad was 1st in it was fine and dandy, but the past few weeks we noticed (due to the freezing weather) that the rad was only hot at the top and cold at the bottom. (It was behind the sofe, so when ever the wife said " is the radiator working", I'd reach behind and touch the top, and tell her to go put on a jumper.. Opps)
The radiator that we branched from is the same, alothough not as bad. All the others in the house are peachy.

Oh and I've bled all rads..

The second problem we had/have. The kitchen sink tap lost its pressure over christmas, and dropped down to a dribble, and then the other day, the bath foillowed suit. I had a read up on this site, and did the flush air lock trick (Hand over the mixer taps and turn on. And now have a wonderfull flow in the kitchen. I tried this in the bathroom, but it didn't do anything.

Could the two be conected?

Thanks in advance,

Apip

[thedoctor]

The first question is covered in the Central heating section of the projects pages. The possible air lock upstairs will not be cured with the thumb over the mixer method as the cold pressure upstairs is probably from the tank and therefore not strong enough to force the air back. Mains pressure cold needs to be forced into the tap to push the air back.

[Apip]

Thanks for that. Hosetime ahead..... The wife will be happy.

Are the two problems connected though?

[Apip]

Thanks for the reply.

Arethe two problems connected woulkd you say?

[thedoctor]

No, the central heating system is run seperately from the domestic hot water. See our projects on domestic hot & Domestic cold water systems and all of our projects on cetral heating. You can then understand how it all works in your house.

[markflip]

The only thing i can suggest is that the rad is sludged up in the centre and the hot water is finding the path of least resistance through the large veins around the top and sides, although I'm surprised if it's a newish radiator. Air will always find its way to the top of a radiator so cold at the top is the ususal symptom for airlocks.

Close the rad valves both sides, drain the radiator into a bowl, either by means of a drain cock in the radiator tail, if fitted, or by loosening the compression fitting to one of the valves and it speeds it up if you open the bleed valve to allow air into the top. Remove the radiator from the closed valves (thus no need to drain whole c/h system) then take it outside and force water through it with a hose and see what comes out, if it is very sludgy wash it through both ways until the water flows through it clear. If it is that dirty, the whole c/h system should be given a thorough flush through and clean, don't forget inhibitor on refilling.