Any advice following rad replacement...

[BobDobelina]

Hiya,

I have a wall mounted glowworm, quite old, three rads up, two down.
I had a very leaky rad downstairs, so replaced it yesterday.
Not sure if I did it right, but I turned off the tap supplying the water tank in the loft, attached a hose to a drain point downstairs, and let it run till all the water came out.
Replaced the rad, turned the tap back on, and went round bleeding all the rads.
Trouble is now, the two rads downstairs are stone cold. heat seems to be coming down the supply pipe till it hits the first rad, but then after a few inches, the pipe is cold. I've tried flushing water through the bleed valve to get it running through, but it doesn't do any good.

Also, there's an expansion tank immediately above the hot water cylinder, and it doesn't fill with water any more - is it supposed to? If I push the ballcock down, nothing happens.

There was no water coming out of the hot tap this morning either, but by the time I returned home tonight, it had started to sputter out.

The pump seems to be running a bit noiser than it probably should, and there are some gushing/burbling noises coming from the boiler.
It all seemed to work fine till I swapped the rad, have I done a bad thing???

Any advice appreciated.
Darren

 

[bengasman]

Sounds like you have an airlock. There are ways to push it out with mains pressure but that is a bit tricky as you could well cause a flood. Keep bleeding the rads and make sure your pump does not run dry otherwise it will die rather quickly.

 

[kevplumb]

bleed the pump

turn the rads off that are working

 

[Slugbabydotcom]

there's an expansion tank immediately above the hot water cylinder, and it doesn't fill with water any more - is it supposed to? If I push the ballcock down, nothing happens.

YES it should let water through

Is the tank empty or full?

Do you have one or two tanks above cylinder level?

I am trying to discover whether you have a single feed a.k.a. 'primatic' hot water cylinder ^^

have you opened the valve fully that feeds cold water to this 'expansion' tank?

Could also be a blocked or sticking balltap but the more you can tell me the more I can tell you

Dont go running around trying to clear airlocks until you know the water is getting into the system

When you 'bled' the upstairs rads did you get water out after the air or did you give up after ten minutes and shut the bleed valve off anyway?
_______________________
moderator

edited to correct quote

 

[kevplumb]

Also, there's an expansion tank immediately above the hot water cylinder, and it doesn't fill with water any more - is it supposed to? If I push the ballcock down, nothing happens.

missed that

is it connected

 

[BobDobelina]

Hi chaps, thanks for the responses

Yes, there are two tanks above the cylinder, a big plastic one directly above the cylinder, and a smaller one above that in the loft.
The cylinder and tanks look like fairly recent additions to the system - the cylinder is one of the foam covered jobs if that helps.

anyhoo, the two tanks are fed from the same water pipe. What I couldn't get me head around is that the shutoff tap is situated between them, not before them...
Ayway, the first water tank is half full at the moment - the level seems to have gone up a bit, dont know how though, as the ballcock valve is open and nowt is comin out.

When I bled the rads, I started downstairs, getting all the air out till wtar ran through, then moved upstairs and did the same. I did the vent that sticks up over the top of the pump as well, and I loosened the screw on the pump and water trickled out. I've re-bled several times, and there doesn't seem to be any air left.

It has to be something daft though, as it all worked fine till I swapped this radiator.
Because the rad was 13cm shorter than the old one, and due to access problems with the pipework, I used a flexible steel braided hose to bridge the gap between the pipe and the rad - there's no valve, it runs straight in - would this cause a problem??

 

[Slugbabydotcom]

The larger storage tank is the one that feeds your hot water, the other is the expansion tank which feeds your heating. This one should only be half full to allow for the water in the system to expand when it heats up.
Pushing down the balltap in either of the tanks should result in water coming out. If this doesnt happen you have either not turned the water back on properly or one or both of these balltaps are blocked. They cost about a fiver each if you fancy just putting new ones in

What I couldn't get me head around is that the shutoff tap is situated between them, not before them...

The rising main comes up and feeds both tanks I take it that you mean that it tees 2 ways to feed both tanks and the valve that you refer to is only shutting the water off to the expansion tank in the loft

I've re-bled several times, and there doesn't seem to be any air left.

You know theres no air left when theres only water coming out
Always bleed radiators with the system turned off

I used a flexible steel braided hose to bridge the gap between the pipe and the rad - there's no valve, it runs straight in

When you said on the first post "Have I done a bad thing" The answer is yes.
I would consider using a flexi tap connector for this is 'bad practice' unless that was what the flexi pipe was specifically designed for and although I wouldnt do it, it will work and I can see where you are coming from. You can get straight through rad valves from good plumbers merchants
The real bad thing that you did was to not put a valve on your radiator because if you have tried everything else in the other posts you now need to take this rad off the wall and flush water through the valve at either side to clear the airlocks


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