‘Bleeding radiators is easy, like burping a baby’

28 July 1998

I will admit that as far as objects of desire go, they do not come much more obscure than the humble radiator key. It does not even really qualify as a key. It is just a little quadrangular wrench that, so far as I am able to discover, does not fit anything but radiators. It is a tool that does one job, and a seasonal one at that: it enables you to bleed the air out of your radiator by loosening the little recessed nut on the unit's right flank. Even “tool” is too grand a title. It is really just a knob that does not stay on, one of those things that spends more time missing than found. It should be right there in the bowl with the pesetas, paperclips and fuzzy breath mints, but it is not.

Like most people, I have more than one. A cursory search through all the usual drawers and jars turned up no fewer than three, which by my rule of proportional object displacement means there are at least three more that I cannot find. Two of these keys are identical die-cast aluminium affairs, but the one I always use for bleeding is brass, with nice round grip-holes, a large, mouse-ear handle and two bleed-faster stripes cut round the tapered barrel. I have no idea where I got it, but it obviously dates from an era when even the most marginally futile object was possessed of some style. While I could hardly get away with saying it out-performs plainer keys, it has a satisfying weight, and it makes a nice sort of blokeish talisman.

Bleeding radiators is one of my hobbies, and it is a distraction I would recommend to anyone who works from home. It is easy, and highly satisfying in a vicarious sort of way, like burping a baby. My devotion to this routine maintenance procedure began two years ago, after a repairman came round to fix my central heating. He produced his key and started bleeding and, with a shake of his head, gave me to understand that a real man would never let so much air build up in his system. He asked me when I had last bled the radiators. Afraid to say "never", I lied and said I had done it the previous winter. He did not believe me. For this humiliation I paid a huge call-out fee, and the radiators stayed cold. When a week later another repairman pinpointed the real problem in the boiler tank, I swore I would never be duped again. The next time a repairman suggests I may have excess air in the system, I will brandish my favourite brass key, Old Bleeder, and say, “There is never any air in my radiators. Let's stop playing games, shall we?”

The radiator key could be said to be cousin to the now-extinct skate key, another single-purpose tool with a high misplaceability rating. Although indisputably an adult thing, the radiator key looks like the kind of object boys always have in their pockets. Even now, if I saw one lying in the road I would probably pick it up, which is more than I can say about your 10-pence coin.

According to the man at the ironmonger’s, the standard radiator key fits 90 per cent of all radiators. While there I bought a new one (brass, milled barrel pierced by a cylindrical handle, stopcock-style) for 95p. I suppose I do not really need to be adding to my collection, but there is not much else to do in the off-season.