Bottom Of Radiators Cold

[Paul S]

On both of my radiators that fit underneath bay windows, the bottom half of the radiator in the middle (long) section does not heat up. Both ends of the radiator, and the top of the middle section does get hot. Does this indicate some sort of blockage in the radiators? And if so, what would be the best way to relieve the problem?

Thanks Paul

[Alan]

That would be sludge then. Remove radiator, take outside, and clean out with a hose until it runs clear. Repeat for every affected rad in the house. Watch out for spills of dirty brown water on carpet when removing.

Alan.

[Christian McArdle]

That is usually sludge in the radiators. Not only should each radiators be totally cleansed (either by taking outside and hosed, or using the often overpriced powerflush), but afterwards ensure that you run for a week or two with a desludging chemical. After two weeks, flush out following the manufacturer's instructions and refill with a corrosion inhibitor.

It was this lack of inhibitor that probably led to your system's current sorry state.

You may wish to find out why there was insufficient inhibitor in your system so the problem doesn't recur. Some possibilities:

1. The system has a leak, so the water (and inhibitor) leak away and is replaced by fresh water (sans inhibitor).
2. The system occassionally or constantly ejects water through the overflow/pressure relief.
3. A misguided plumber couldn't be bothered to install some, perhaps in the hope of drumming up business, or, perhaps, through complete ignorance.
4. The inhibitor is so old that it is no longer effective.
5. An insufficient quantity, or inappropriate type of inhibitor was used for the type of system.

Christian.

[Paul S]

Thanks for the reply. Any way of flushing the whole system without having to remove individual radiators?

Thanks Paul

[Christian McArdle]

You could powerflush, but this is very expensive. If the radiator has got as bad as described, you are unlikely to have much success with desludging chemicals alone.

Christian.

[Paul S]

Ok, thanks. Looks like I'll be removing the radiators then!!

[Des Higgins]

hmmmm .... thinks..... I have just had my system drained down recently and I do not know if the guy used inhibitor or not. Short of trying to find him again, is there any way to find out if he did use any (now that I write that; that looks like a silly question) or can you just put more in?

Des

[Christian McArdle]

Flush the system out thoroughly first. Then refill using inhibitor. You want to get rid of most of the old dirty water before topping up.

Christian.

[fred]

In article , Des Higgins writes

If you drain a little from a radiator bleed vent it should have a dark straw type colour and a noticeable smell, however if there was none in there at all then that straw colour could be rust ;-).

The manufacturers used to recommend a test which was IIRC to draw off a small amount from a radiator, just 20ml or so, then dilute it 10:1 with clean water to make about half a cup full (200ml) drop in a clean steel nail & leave for a week. If there is any trace of rust on the nail then drain, flush (with just water) & refill with correct level of inhibitor.

I'd only suggest this if the system had been fully drained & refilled to check whether there was either some or none in a system, if the system was partially drained & then refilled but no further inhibitor added then there may be enough to pass the test, but not enough to protect the system for the next few years.

I'm sure you'll get the 'it's only 20quid so put some in anyway argument', but if your tradesman was a reliable chap(ess) & added the right stuff, then that's 20quid that you can spend elsewhere. On the other hand, any doubts then drain & replace.

bit long that, sorry . . .