# Bleeding Radiators!



## peejay (May 10, 2005)

No, not swearing  

I have to bleed two of our house radiators at least once a day, the rest are ok.

I was thinking of fitting a couple of Aladdin autovents, they are pretty cheap on ebay.

Some reviews say they are good, some say they don't work, anyone got them fitted to their c/h system?

Pete


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## Glandwr (Jun 12, 2006)

You have something wrong with the system Pete. Is it vented or unvented? 
Dick


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## peejay (May 10, 2005)

Haven't a clue Dick, Its an oil fired boiler, how do I tell?

Pete


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## A14GAS (Oct 9, 2014)

Hi peejay,Aladin auto air vents will work but you are only venting the air from the system when you should be looking for the reason air is getting into the system.
A common cause is when the pump switches on it pulls air into the system via the expansion pipe which could be down to bad system design or even the pump speed,this is all assuming you have an open vented system.
Hope this is of some help to you.


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## DABurleigh (May 9, 2005)

1) Ensure you have inhibitor in the system.

2) Check the level in the header tank.

3) Check you are not in an "overpumped" situation, where you are overflowing at least at some point in the cycle into the header tank, and drawing aerated water back in. The header tank will be warm and the loft may have condensation.

Dave


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## A14GAS (Oct 9, 2014)

You will be able to tell if it is open vented as you will have feed tank usually in the loft which tops the system up automatically.
A sealed system will require you fill the system via a filling loop and will also have a pressure gauge.


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## peribro (Sep 6, 2009)

If the system is an old one then it's possible that corrosion is the culprit as this can cause hydrogen gas to be created within the system. If you are able to drain a little bit out of the bottom of the system then see what comes out. If it's black sludge then corrosion could well be the problem. In which case you would need to drain the system through, use a cleaner and then an inhibitor. If the corrosion is very bad then I suppose it's possible that you could have a leak somewhere.


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## Glandwr (Jun 12, 2006)

peejay said:


> Haven't a clue Dick, Its an oil fired boiler, how do I tell?
> 
> Pete


The others have it right Pete. Have a look in your loft for a small header tank. If you have one afterchecking you have water in it, find your pump (in or adjacent to the boiler) there will be a speed switch on it. Try tuning it down a notch.
Dick


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## peejay (May 10, 2005)

I think it may be a sealed system, theres no conventional water tank and header tank like in our previous houses, its also linked in to a solar panel for hot water, perhaps you can tell from the attd photo.

All the radiators were replaced early last year due to flood damage and I'm presuming inhibitor was added, the water in the rads is certainly black.

Pete


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## Pudsey_Bear (Sep 25, 2008)

What a brilliant site this continues to be


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## Glandwr (Jun 12, 2006)

That is a sealed mains pressure domestic hot water supply Pete. As you say no header tank needed with that but you could still have a vented boiler sytem. Are you sure there is nothing it would be quite small.


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## peejay (May 10, 2005)

Just been up the loft again, can't find any sign of a small header tank at all.
There is a 'grundfos' inline pump to the left of the main tank but can't find any other pumps near the boiler which is in the garage below.

Pete


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## Glandwr (Jun 12, 2006)

Sorry Pete can't be of more help withou seeing the sytem. But you are sucking air somewhere. Two last things turning down the speed of th grunfos pump won't do any harm. If it does not cure it turn it back up.
One last thought, you are not bleeding the rads with the pump running are you?
Dick


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## peejay (May 10, 2005)

Thanks Dick i'll have a go at turning down the pump. 

I have been bleeding with the pump running, I assumed that is the only way to force the air out, is that wrong?

Pete


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## Glandwr (Jun 12, 2006)

Definitely wrong Pete! That's where air is coming from. Everything OFF before you bleed. It may take a few times to purge now.
Dick


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## coppo (May 27, 2009)

You need to bleed the radiators when they are cold and not on Pete.

Paul.


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## peribro (Sep 6, 2009)

I'm sure Dick is right about how air is getting in. Also make sure that the system and all the rads are completely cold before you bleed them.


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## peejay (May 10, 2005)

Oops, as you can tell I'm pretty switched on when it comes to this sort of thing. :lol: 

I've got the builder coming on Tuesday to have a look at the system anyway, its under warranty, they are tying it in with a nearby visit, I shan't mention I had the pump running. :roll: 

Thanks to everyone for their help on this thread, what a great bunch you are. :thumbleft: 

Pete


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## Easyriders (May 16, 2011)

Another reason could just be that the radiators are just not level. Check them with a spirit level. If they are not perfectly horizontal, adjust the brackets so they are.

We had one radiator that always needed bleeding. Adjusted the level, and it's been fine since.


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## dghr272 (Jun 14, 2012)

The pump should also be bleed when switched off and cold.

Terry


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