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Radiator bled - no water comes out


 
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eddierobson

from United Kingdom

Joined: 14 Mar 2007
Posts: 7
Location: Lancashire,
United Kingdom

PostPosted: Wed Mar 14, 2007 4:20 pm Reply with quote

Hi,

We've finally got around to bleeding a radiator which has been cold at the top and warm at the bottom since we moved into our house 18 months ago... previous owner didn't leave any keys and we've only just got hold of one. When I bled it I got the expected hissing sound for about 10-15 seconds, then it died down. No water came out. I re-tightened the screw, left it for a few hours, tried again. Same thing happens. I've been doing this two or three times a day for a few days, get a bit of air coming out each time. No water yet.

As a total layman, my guess as to why this is is that there's so much air in the radiator, the pressure isn't enough to push it all out in one go. Am I right, and if so will I eventually get all the air out by doing what I'm doing, or am I wasting my time? Is there anything else I can do to help it along, or anything I should be doing? (I've discovered it's best to do it with the heating turned off, to avoid getting more air into the system.)

Our boiler is a gas Worcester 28CDi. It's on the ground floor of the house, the problem radiator is on the second floor. Any help hugely appreciated.
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Bahco

from United Kingdom

Joined: 08 Feb 2004
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PostPosted: Wed Mar 14, 2007 5:35 pm Reply with quote

Turn all your other rads off and then bleed.

You should get water out of the bleed screw unless it is blocked with sludge or the valves are not open enough,

Consult the FAQ on balancing your rads too icon_biggrin.gif
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scaby

from United Kingdom

Joined: 20 Nov 2006
Posts: 81
Location: Essex,
United Kingdom

PostPosted: Wed Mar 14, 2007 6:26 pm Reply with quote

the 28cdi is suitable for both sealed and open vented, your boiler may be running on very little pressure, is there a 15 mm pipe going out through the wall underneath the boiler? or is there a small feed tank in the loft?
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eddierobson

from United Kingdom

Joined: 14 Mar 2007
Posts: 7
Location: Lancashire,
United Kingdom

PostPosted: Wed Mar 14, 2007 6:33 pm Reply with quote

Bahco wrote:
Turn all your other rads off and then bleed.


Thanks - I've tried that, still no water. I've tried bleeding a couple of other radiators, no problems there, so the fault definitely seems to be in this one. I should also note that the problem seems quite extreme - the entire top half of the radiator is cold, it's only the bottom that heats up.

Quote:
You should get water out of the bleed screw unless it is blocked with sludge or the valves are not open enough,


Maybe it's sludge then. At the moment the control valve is on the hottest setting (which I presume is the most open) but the lockshield valve is tight - should I try bleeding it with the lockshield valve opened up a bit? I assumed that having the control open and the lockshield closed would put more pressure on the trapped air, but as I say I'm very much a layman with this.

Quote:
Consult the FAQ on balancing your rads too icon_biggrin.gif


Cheers!
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gas4you

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PostPosted: Wed Mar 14, 2007 6:39 pm Reply with quote

Open the lockshield a couple of turns and try it. Are the other couple of radiators you bled successfully upstairs as well?
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eddierobson

from United Kingdom

Joined: 14 Mar 2007
Posts: 7
Location: Lancashire,
United Kingdom

PostPosted: Wed Mar 14, 2007 6:50 pm Reply with quote

gas4you wrote:
Open the lockshield a couple of turns and try it. Are the other couple of radiators you bled successfully upstairs as well?


No, there's only one other radiator on the second floor and we don't have a key for it (we have about four different types of radiator here and didn't get given keys for any of them when we moved in). The other second-floor radiator generally seems okay though - maybe not quite as hot as the others, suggesting perhaps we should balance them, but it does its job, unlike the problem radiator which hardly gives off any heat at all.
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Bahco

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PostPosted: Wed Mar 14, 2007 6:54 pm Reply with quote

Bleed them ALL and then balance.

You can get keys from any pl merchant icon_biggrin.gif
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gas4you

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PostPosted: Wed Mar 14, 2007 6:55 pm Reply with quote

Going back to a previous reply post, you have not answered whether it is a open vent system (header tank inloft) or sealed system (15mm safety pipe off bottom of boiler going through wall to outside) icon_rolleyes.gif
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eddierobson

from United Kingdom

Joined: 14 Mar 2007
Posts: 7
Location: Lancashire,
United Kingdom

PostPosted: Wed Mar 14, 2007 7:01 pm Reply with quote

scaby wrote:
the 28cdi is suitable for both sealed and open vented, your boiler may be running on very little pressure, is there a 15 mm pipe going out through the wall underneath the boiler? or is there a small feed tank in the loft?


We don't have a loft, so no feed tank. I can actually see where the pipe runs across from one of the two second-floor radiators to the other, and there doesn't seem to be anything else connected.

There is a pipe that goes down out of the boiler and out through the exterior wall.
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eddierobson

from United Kingdom

Joined: 14 Mar 2007
Posts: 7
Location: Lancashire,
United Kingdom

PostPosted: Wed Mar 14, 2007 7:03 pm Reply with quote

gas4you wrote:
Going back to a previous reply post, you have not answered whether it is a open vent system (header tank inloft) or sealed system (15mm safety pipe off bottom of boiler going through wall to outside) icon_rolleyes.gif


Sorry - that post appeared whilst I was replying to another one, so I only just saw it a minute ago.

There is a safety pipe, yes.
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gas4you

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PostPosted: Wed Mar 14, 2007 7:03 pm Reply with quote

What does the pressure guage read. Should be approx 1 bar cold, up to 2 bar hot rads. Have you been topping up system via filling link/loop after each attempt to bleed rad and air stops?
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eddierobson

from United Kingdom

Joined: 14 Mar 2007
Posts: 7
Location: Lancashire,
United Kingdom

PostPosted: Wed Mar 14, 2007 7:07 pm Reply with quote

gas4you wrote:
What does the pressure guage read. Should be approx 1 bar cold, up to 2 bar hot rads. Have you been topping up system via filling link/loop after each attempt to bleed rad and air stops?


I wondered about this - it was one reason why I posted here, as I didn't see it mentioned in any of the guides to bleeding that I found. The pressure guage is really low, close to zero. I haven't been topping up the system because I'm not sure how.
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gas4you

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PostPosted: Wed Mar 14, 2007 7:27 pm Reply with quote

You need to top it up to around 1 bar icon_exclaim.gif You may have a sliver flexible connector under the boiler with a tap at each end. I'm not sure that Worcester 240 has a built in filling link that needs a special tool to insert to operate. This would be white, about 3 or 4" long and about 3/4" diameter.

If not you could back fill on a drain off point with a garden hose.
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TheBigMatt

from United Kingdom

Joined: 26 Feb 2007
Posts: 42
Location: Sussex,
United Kingdom

PostPosted: Wed Mar 14, 2007 8:07 pm Reply with quote

Hi,

I have a 28Cdi. I assume they are all the same???

On mine, you need to look at the underneath of the boiler, remove trhe bottom grill. You should see a round hole, into this you need to insert a special tool that comes with the boiler.

It is made out out white plastic and looks like a "T" with a couple of rubber seals on the long end.

Insert it and turn it 90 degrees, these should enable mains water to enter the system. Next to it is a grey knob (tap/valve..whatever you call it)

Undo this (like a tap or screw) and you should hear water floing. Watch the Pressure gauge and turn off the Tap when the pressure hits 1 bar or slightly above.

CAUTION....do not undo the Tap too much (it might come out...i just don't know), also do not do it up too tight, just enough to make sure it's off.

Turn the "T" back 90 degrees (isolating the mains water) and remove the "T".

A small amount of water might come out. Ckeck back later to make sure nothing is dripping or leaking.

Anyway...that's how mine works. If you do not have the "T" then start hunting..

Maybe a good Plumbers Merchants (not a DIY Store) might be able to order you one.

Hope it helps.

Matt icon_smile.gif
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eddierobson

from United Kingdom

Joined: 14 Mar 2007
Posts: 7
Location: Lancashire,
United Kingdom

PostPosted: Thu Mar 15, 2007 10:22 am Reply with quote

TheBigMatt wrote:
Undo this (like a tap or screw) and you should hear water floing. Watch the Pressure gauge and turn off the Tap when the pressure hits 1 bar or slightly above.


Found the "T", did this, problem sorted. It was indeed due to a lack of pressure in the system. I've now managed to successfully bleed the radiator.

Many thanks to all who replied, this has saved me a massive amount of time, hassle and (potentially) money, and I've learned a couple of things that will be useful in the future too. icon_biggrin.gif
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