There's a Derren Brown mentalism piece in one of his TV shows where he gets into a taxi (along with his camera crew[1]) on the North side of the embankment across the river from the London Eye, rattles off some patter to the cabbie as they're getting in, and asks to be taken to the Eye. Then, despite the fact it's staring them all in the face just across the river the poor driver is humming and haaing "Oh I know it's around here somewhere, um, err ...." - completely unable to see - or register - it.
And Robert Pirsig in "Zen and the Art of Motorcycle Maintenance" talks about 'gumption traps', where you can't see the bleedin' obvious right in front of your nose.
So when you get asked to look at a tank in the attic that's overflowing the first thing you look at is the filling valve ('ballcock' to you civilians). And then you check it again, in case you missed something first time. Because 9 times out of 10 that's the problem. There are other mechanisms which - like Rare Diseases in medicine - are rare. In particular, in a conventional old-school British system with tanks (usually in the attic) for cold water storage and one for the central heating system, a leak within the hot water cylinder's heat exchanger coil can allow water from whichever tank has the higher water level to get through to the other one. But that's rare. Very rare.
There's also an interesting thing called 'pumping over' that can go on in central heating header tanks, involving water getting either expelled or sucked in to the system via the vent pipe (the pipe with the upside-down 'U'-shape with an open end over the tank) which results in the tank getting filled with hot water, clouds of mist filling the attic in cold weather and massive corrosion occurring in radiators and boiler over a period of months or a few years. So when you get called to look at an installation that has both of these symptoms the true Rogue Plumber will get distracted with the pumping-over problem, miss the obvious cause of the overflow and tell the customer he needs a new hot water cylinder.
And unless the customer has the nous to get a second opinion from another plumber who correctly diagnoses and fixes the problem our RP hero is set for his 15 minutes of fame and free advertising on Rogue Traders.
[1] and sound crew, lighting, make-up, key grip, mole grip, catering, fluffer, fluffer's mate, best boy and Ken Morse on Rostrum Camera, no doubt.
No comments:
Post a Comment