Bleeding Radiators? Needed? Why? How?

skylight

I have been in my present abode for 8 yrs and was told recently that I should bleed the radiators every year. (Have never done so)

But why?
Do I actually need to?
What does it do?
And if so, how?

moneysavingplumber

Not always, especially if you have a combi boiler, as I had a call today from a client who had done just that and as a result his boiler had 'locked-out' due to it losing pressure.

Some systems unfortunately do require bleeding, usually as a result of poor intial design causing the system to intake air and failing to expel it. It can also be caused by corrosion causing joints to leak slightly and then suck in air, as well as worn valves. It can also be caused by incorrect materials, such as older non-barrier plastic pipe.

The obvious signs are radiators hot at the bottom and cold at the top, and gurgling in the system, although there could be other causes of this. If you have a gravity, open-vented system (small tank in the loft usually next to big cold water storage tank) you can bleed the radiators carefully, ensuring the pump is OFF, but be very careful not to open the bleed vent too far as the pin may shoot accross the room leaving you with your finger over the hole! Have a rag or piece of kitchen roll held tightly around it as well to catch any sludge that may come out. Make sure the small header tank has water in it and that the ballvalve is not stuck in the up position, a common problem at the end of summer.

If your heating works fine, the radiators are hot all the way up and it makes no horrible noises, there's no need to bleed the radiators.

A well-designed, properly maintained system will not need bleeding. You might be lucky. If it has any of the above symptoms the causes should be investigated and remedied if possible anyway.

skylight

All my rads are fine (just checked) and there is no gurgling, so I wont worry about it!

The system is old (although not ancient).

I will keep an eye on this though and thanks for the answer!

(Was told to bleed by someone who knows everything about nothing!)

Al_Mac

charlotte664 wrote:

(Was told to bleed by someone who knows everything about nothing!)

Find a few like that around here:D

Queenie

Al_Mac wrote:

Find a few like that around here:D

:rotfl: ROFLMAO :rotfl:

You *owe* me a new monitor!!

Queenie

If the occasion *should* arise where you may need to bleed your rads ... I bought the "keys" to do it with in one of the supermarkets!

Here's a link (with a pic) on how to do it should push come to shove at any time in the future

Heating Systems - Darlington Housing (UK)

HTH

starlite_2

I think you should bleed them , even with a combi boiler.
We have one, and soon after moving into our flat we got a sudden and really bad leak from one radiator.
Being clueless we called out a plumber who then charged us £90 for bleeding the radiator...not good!

moneysavingplumber

starlite wrote:

I think you should bleed them , even with a combi boiler.
We have one, and soon after moving into our flat we got a sudden and really bad leak from one radiator.
Being clueless we called out a plumber who then charged us £90 for bleeding the radiator...not good!

Are you prepared to pay a similar amount for a plumber to come and top up your system pressure when the boiler fails to work after the pressure has dropped? Manufacturers instructions stipulate that system pressure should only be topped-up by a competent engineer. A radiator leaking would not be solved or avoided by someone bleeding it so I imagine there is more to the story than that. The problem you describe would have most likely been caused by corrosion to one of the air vents, a problem that would have been exacerbated by an attempt to bleed the radiator unnecessarily. The other possible scenario is that it was leaking from the valve packing gland nut, remedied simply by tightening it, and nothing to do with bleeding. Whether you were conned or not is another matter but it is incorrect to advise people to bleed radiators against a professional's opinion that you shouldn't, especially as, with all due respect, you have described yourself as 'clueless'.

As I previously stated, radiators do not need bleeding on a system that is working well and has no obvious symptoms of air ingress.

innovate

I agree to some extent with moneysavingplumber - rads on a combi-system shouldn't normally require bleeding, and bleeding may result in no heating at all because the pressure has dropped too much.

However, moneysavingplumber, there are good reasons for bleeding radiators even on a combi system, and it shouldn't always require paying an expert to do this. E.g. I recently had a radiator moved (by a qualified heating engineer), and it took several days of bleeding for the air to all escape from the system. I surely wouldn't pay for an engineer to come for the daily bleeding!

I have a big Bosch Worchester combi-boiler, and whilst it is not obvious where the top-up valve is and the instruction manual doesn't mention it (and also not that the system must only be topped up by a competent engineer), I asked the engineer who moved the radiator 1) where the valve is, and 2) what pressure the boiler should be set to. Armed with this information, it's now not beyond my wits (even though I am blonde ) to bleed my radiators.

starlite_2

well...i don't think anyone reading my post would take my word for it and go ahead and end up ruinibng their system.
there was no call for such a shirty response.
I just wanted to add my experience. In this case the flat had been empty for almost a year before we bought it- not sure if that contributed to it- and the plumber certainly did nothing more than bleed the radiator. the problem was then resolved. whether he was fair to charge such an amount for that is another matter of course.

ajbaker

http://www.autovents.net/uk/

One on the highest radiator up stairs may suffice, but I believe one on each raditor is preferable.