My late-1950s house has a typical gravity-fed CH+HW system with a back-boiler, first-floor HW cylinder and cold-water tank in the loft. The CW tank is circular and made of some black rubber-type material and must be at least 50 years old if not more.
Originally the CW tank had no proper lid, just an insulation jacket that was spread across the top and wrapped down around the sides. This perished about 5 years ago, so I fitted a new insulated jacket and also a proper circular black plastic(?)-type tank lid. For some reason I simply could not get a lid that was an exact fit - maybe a mismatch between new metric size lid and old imperial size tank, or perhaps the tank has just 'bulged' a bit over the years ?? - anyway I got the best fit that I could.
It is difficult to pin-point the exact cause of the current problem, but it would appear that water is condensing on the underside of the lid and running down towards one particular 'corner' of the tank where there is quite a bit of limescale type stuff on both the underside of the lid and around the lip of the tank edge. The water then drips over the top of the tank side and down the outside, but behind the jacket, before finally dripping off the bottom of the tank and onto the floor, where there is now a small (but possible growing) wet patch. No idea how long this has been happening, but there was no evidence of it about 9 months ago.
Any ideas please as to what may be the cause of the problem and how best to cure it?
Originally the CW tank had no proper lid, just an insulation jacket that was spread across the top and wrapped down around the sides. This perished about 5 years ago, so I fitted a new insulated jacket and also a proper circular black plastic(?)-type tank lid. For some reason I simply could not get a lid that was an exact fit - maybe a mismatch between new metric size lid and old imperial size tank, or perhaps the tank has just 'bulged' a bit over the years ?? - anyway I got the best fit that I could.
It is difficult to pin-point the exact cause of the current problem, but it would appear that water is condensing on the underside of the lid and running down towards one particular 'corner' of the tank where there is quite a bit of limescale type stuff on both the underside of the lid and around the lip of the tank edge. The water then drips over the top of the tank side and down the outside, but behind the jacket, before finally dripping off the bottom of the tank and onto the floor, where there is now a small (but possible growing) wet patch. No idea how long this has been happening, but there was no evidence of it about 9 months ago.
Any ideas please as to what may be the cause of the problem and how best to cure it?