Radiators, HELP!!

matthewwoodward

I have just moved into a 3 year old house with a boiler (not combi) Which heats our radiators.
Anyway, some of the radiators do not heat all over. They get very hot at the base but the top is either warm or cold. I know this means they need bleeding. But NO! I have bleed them and yes a little air comes out but then no water follows, I leave the valve open for ages but it doesnt help.
I have tried turning off all the others, turning the pump to full speed and then bleeding but this still doesnt help.
ANY Ideas? I dont really want to pay a plumber to come out so was hoping someone on here could help.
Matt

derrick

If no water follows, they are part emtpy, where are they situated? top floor? if so it could be that your ball valve in the loft has stuck and therefore not allowing them to refill, will need to check the small tank in the loft is full and that the ball valve is working and allowing tank to fill when you bleed the rads, also bleed them with the pump off.

weekendwarrior

Like the post above says and this here- Bleeding a radiator
you should always bleed radiators with the heating switched off

kenshaz

Check your small header tank which feeds the system,the ball valve may have stuck in closed position ,and is not letting water in ,or the red gate valve in the cylinder cupboard is not allowing water to pass from the header tank to the system and the heating system is running half empty or dry.

You have an airlock
Regarding the air lock

---

air could have been drawn in when when the system was drained .


or the system is full have sludge ,make sure the system has water in and put a cleaner and inhibitor in the system via the small header tank.The sludge prevents circulation and blocks water movement

or if you have thermostatic valves have jammed

silvercar

I have a similar problem, one radiator takes 45 minutes to get warm! Doesn't need bleeding and I know its at the end of the line, but 45 minutes!

If it makes a difference we have another radiator currently disconnected from the loop at the moment, so the flow and return are not joined somewhere on the circuit, they just end at valves. But this is all at the other "end" of the loop.

Sorry if I've hijacked your thread, but our solutions may be similar.

espresso

silvercar wrote:

If it makes a difference we have another radiator currently disconnected from the loop at the moment, so the flow and return are not joined somewhere on the circuit, they just end at valves. But this is all at the other "end" of the loop.

Yes this will make a big difference as your system will no longer be balanced. You problem should sort it's self out when the radiator is re-fitted, assuming that it was correctly balanced in the first place.

matthewwoodward

I will have a look for this small tank. Will it be the one right above the immersion we have? There is no small tank in the loft.
I shall check this ball valve is ok.
If you bleed rads with the heating off is there enough pressre to push air out??
I thought if it was sludge in the rads they would be hot at the top and cold at the bottom.

msun

If you have no expansion tank you may have a "sealed system". In that case there will be a small pressure vessel, (typically red in colour) somewhere in the circuit perhaps with a pressure guage. This may need topping up with water from the mains to bring the pressure up especially if there has been loss of water from the system due to leaks or bleeding of the radiators.

Cheers from Mike

a&akay

It may be that there is very little head between the feed and expansion tank water surface and that in your radiators and therefore no gravity force to drive out the air. In these situations I have attached a short length of plastic hose to the air vent on the rad with the bleed screw removed (use blutack or similar to create a good seal if necessary). Suck on the hose and you will create extra head due to the vacuum. Can taste unpleasant if you have Fernox or similar in the water. Have a paper towel handy to catch excess water as you panic trying to stem any excess flow while your screw back the bleed screw!

matthewwoodward

Thanks guys!
I looked in my airing cupboard and right above my immersion tank is a small red tank which I guesses was this expansion tank you all spoke of.
Anyway, I looked at the pipes coming out of it and found a valve, one with a 1/4 turn screw, and the valve was shut. I thought this was strange so opened it. Then beneath that was a key type valve again 1/4 turn so I thought what the heck give it a turn. Instant sound of water rushing somewhere. I turned it off and gave the first rad a bleed. SWEET! loads of air then sweet water. Kept turning this tap open and bled them all till no more air.
Now I know the women who had the place before us knew nothing of rads so could these 2 valves have been shut since the house was built?
I have closed them both now, not really knowing what they did, are they ok closed? A few drops of water leaked from a seal when I opened them I assume from not being used SO I feel better shutting them.
What I thought was if the rads need bleeding again I will just open the bvlaves then.
Is this all ok? sorry for spelling, in a rush.
Matt

kenshaz

Just need to fill the system,then bleed ,then you can shut them off until you get the leaky valve sorted ,it is only an initial feed and top up tank ,you should get little loss from evaporation