any plumbers out there ?

[marinabrid]

Hi all,  wondered if anyone with plumbing brains can assist
in our house its 3 floors, on the top floor we have a ladder rad in the bathroom, this is the highest point of any rad and above it in the loft is the header tank. its a normal vented system with a ideal boiler.  not a combi
The top 3 rungs of the ladder rad are not hot.  the rest of it is, i can bleed it and some air comes out most days but then the air stops and no water will come out.
i took the vent off  which is located on the very top and  peered down,  the water level was just where it finished getting hot.   i topped it up through the vent hole and i could see the water circulating around the rad and the top rungs then got hot,   thought i had cracked it .

sadly not,  few days later i bleed it and more air comes out   then some water.     next few days it goes back to the way it was.    it topped it up again and it was fine for another few days.  so    where is the water going.   there is no damp patches all the other 15 rads in the house are full and water comes out when you bleed them.   just this top one causing problem.  any ideas welcome,  it don't really cause any bother even in winter it was warm enough without the top rungs getting hot.   just trying to work it out.   plumbers in the area are a nightmare so i won't call one unless its a dire emergency,

[gregers]

no you lost me on the 1st sentence 
BUT join and ask here m8ty,very knowledgeable on there.

www.diynot.com 

[Chrispb]

Had a similar problem with one of my bedroom radiators, always needed bleeding a few times in the heating season to keep it hot right to the top, then a few years ago fitted a ladder style towel rail which is about two feet taller than the bedroom radiators so now air gets trapped in the towel radiator.
You can get automatic vent valves for these rads which may cure your problem.
Same type system as yours just aeration building up to the highest point, wouldn't worry about it.

[marinabrid]

have tried a auto vent     but for some reason they don't seem to work well    I can still unscrew it and let air out,,   what puzzles me is   where is the water i topped the rad up with a few times going.    i have checked the header tank   ballcocks, overflows    practically everything i can think of.

[Chrispb]

Yes I can get more out by undoing the bleed valve, as to where the water goes to, it will be displaced to the header tank until you open the bleed valve.
So there will be a small rise in the water level in the header tank until you open the bleed valve then the level will return to normal.

[marinabrid]

thanks for the info Chris,     so why then won't the water stay in the system and in the rad i have topped up.  it was a new rad 2 years ago and got hot all the way up to the top    then a few months ago it just started playing up.

[Chrispb]

I've lived in my house 34 years and I've always had the problem, obviously boiler, pump and various radiators have been changed and upgraded the system to fully pumped as the hot water used to be gravity but still get it.
I've always run my boiler at maximum temperature and that probably doesn't help.
As you have only recently started having the problem have you made any change to your boiler stat setting or increased the pump speed?

[marinabrid]

no  nothing changed      the pump runs on speed no.2 setting   have tried it on sped 3    no difference.   i have closed every other rad and tried  and still it won't get hot at the top.

i topped it up again last night and put around 2 litres back in ,   will see how it goes.

[Stumuzz]

I've had a quick google search for your problem.
Any solutions I copy and paste here that work for you I claim no credit for.

Have a look see if you have a bleed valve in your airing cupboard. It is a tall copper pipe with a small screw valve on the end. It should feel hot all the way to the top. If not slowly unscrew it and you should hear air hiss. Checking this regularly has cured the problem with my bathroom radiator. I too was always bleeding it because part of it was cold. I am on BG 3* cover so I can call them out for free. The gasman told me to bleed the bleed valve instead.

Posted by Poppy9 at

http://forums.moneysavingexpert.com

Also from the same site;

Turn all radiators to full on, run system for at least half an hour and then bleed highest radiator in the house.
Check pressure on system and if necessary top up system.
And finally repeat after another half an hour.

posted by fairenoughclough.

Stuart.

Remember to turn the system off before bleediing or air will be drawn in.

[Stumuzz]

Locate the pump and find the flow regulator. Make a note of the setting, before using a screwdriver to turn it off and on very quickly for a few times. If this is still unsuccessful, try bleeding the pump itself. The bleed valve should be visible on the top of the pump casing. Open and close it with a screwdriver very quickly. If you hear the sound of air hissing - you have found your fault

Posted by Champer at

https://uk.answers.yahoo.com/question/index?qid=20090328040349AAjQvM4

  be sure to do this with the pump switched off


Stuart.

[marinabrid]

thanks for the tips   will have a look for a bleeder in the airing cupboard.    didn't know though you had to bleed with the system off,    i usually do it when its on.