Bleeding Radiators - no valve on either top end?

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paddyodoors

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Hi

I am a novice radiator bleeder, and have a problem - we have a rad where the top is cold and bottom warm, so suspect just needs to be bled to drain out the trapped air - however there is not a valve on the top of the rad at either end to do it. Anything I have looked up always refers to this valve.

There are two white caps on the pipes that connect to the rad at the bottom - but I dont want to risk undoing either of them in case water pours out everywhere.

Also a more basic question - do I have to turn off the heating or stop the water flor from the tank when I do it?

thanks
Paddy
 
I have some double rads and the valves are on the inside of the rad rather than at the end - Grasp the top of the rad with your hand, as though you are 2FT tall and want to climb up and run your hand along the rad - Your fingers may find the valve on the side facing the wall
(awful description, but am sure you will understand)
If its a double rad, there will be one for each rad.
 
paddyodoors said:
..
Also a more basic question - do I have to turn off the heating or stop the water flor from the tank when I do it?

thanks
Paddy
Click to expand...
You will need the heating on and the rad beginning to get warm before bleeding. Bring an old towel or rag with you to catch the water as it begins to flow from the bleed-valve, which it will once all the air is gone.

Best of luck.
 
Found the valve - exactly as you described Conshine, was surprised to find it - not exactly convenient to get to are they - so now I know where to attack.....

Now any idea where I can pick up a key to undo it?

thanks again
Paddy
 
Sorry to steal the thread but I was just looking for some advice on the same subject.

I was painting my bathroom and I took off the radiator so I could paint the wall behind it.
After I put it back on I opened the valve at the top ane let the water flow.
Everything was fine until the Gas Boiler started working VERY LOUD and I could hear some weird noises coming from radiators around the house!
I think some air might have gotten into the pipes.

What do I do?
 
When you refill a rad the water has to come from somewhere, if you have a feed and expansion tank in the loft, then when you fill the water level will drop, which in turn will operate the ball valve, if you have a sealed system then you will have to open the valve(s) at the filling point, if your really lucky you could have the tank in the loft and a filling valve (crazy i know), if your ball valve is defective or you don't open the filling valves, then when you bleed the rad you are really just robbing water from other rads, which will drop the water level/pressure, possibly allowing air in to boiler, long story short make sure you have filled the system properly, Gary.
 
"when you bleed the rad you are really just robbing water from other rads, which will drop the water level/pressure, possibly allowing air in to boiler"

Damn, I didn't think of that. I have only moved in here two weeks ago and I don't really know what system this is. How can I check it?. The hydrometer on the gas boiler shows 0 so it might be a closed system.
There is a tank in the attic but I have no idea what I need to do.
Please help!
 
The tank in the loft may or may not be for the heating, but there is nothing wrong in making sure it has water in it and the ball valve operates properly, once your happy, start your search for filling valves, this could be proper filling loop which is a chrome flexible connector and has two little knobs at each end or a point that can receive a straight headed screw driver, which you would turn in a controlled manor to fill system(any time you refill a sealed system, be very careful not to put to much in, anything over 2 3/4 Bar on boiler pressure guage is bad, 1 1/2 Bar is good),filling loops normally can be found on pipe work under boiler, in hot press or anywhere, you may have a homemade filling loop which would be two gate valves and a big brassy non-return valve, if it is this then the hot press is best place to start your search, if you have a cylinder look at the pipe work coming out of the side of the cylinder and follow it around to see if you can find filling point described, you may have a tank fed sealed system which will not allow you to achieve a good system pressure as it's not mains water it's using gravity, so 1/2 a Bar on boiler guage would be great, if it's this type, look for a gate valve with a brassy non return valve( if you don't know what one looks like go to diy shop and have a look,same for chrome filling loop), on some funky gas boilers they have a integrally filling point so check manufactures instructions, you will have to bleed whole system once you have found filling point. On another point have a look at fernoxs or sentinels site about dirty system water to see if it applies to you, Gary
 
Ok, thanks a lot for your help. I'm at work at the moment but as far as I remember there are three pipes coming into the gas boiler from the bottom.
The one in the middle has a yellow 'hand' and must be for gas. The ones on both sides of it have red knobs - those would be filling valves I presume.
Now, I will first check the tank as you suggested. However, if I have to use the filling valves, do I open both of them and just watch the hydrometer? Do I need to do anything else like open bleeding valves on the rads or can I do it at the later stage?
Also, will this get rid of the air in the boiler - it's really generating some weird noises when I turn either CH or HW on. I wouldn't want to damage it in any way.
I really appreciate your help so far.
Thanks again.
Sy
 
No, under your system boiler you would have a flow pipe, gas pipe and return pipe, normally in that order, on these pipes you would have isolation valves which allow the boiler to be isolated and drained independent of your radiator circuit, as you have a system boiler and not a combi it is less likely you that you will have a filling loop under the boiler, so the best place to look is in the hot press, you need to start by under standing how your system fills up, once you know you can than pressurize, then bleed lowest rads first , than pressurize, then bleed till you are happy the rads are bled, than run the boiler which has a auto air vent to vent air, than pressurize, then monitor, if its still noisy double check rads, you may find you have to let it run for day or two for the air to clear, *if you don't have a pipe to discharge water to a safe place then over pressurizing will cause water damage*, that is if it's a mainswater fed, tank fed is less of a issue, if you are unsure get someone in to walk you threw the system, it's easy to refill a system but it's also easy for it to go wrong, better to be safe than sorry, Gary.
 
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