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Location: Eccles, Gtr. Manchester, Lancs
Date: June 2009
Description: The complaint was that the hot water ran at full pressure for about thirty seconds and then would slow down to nothing. Over a period of months the slow down had become worse until only a few seconds worth of water would flow before there was nothing more than a drip. We arrived to view the problem and after checking out the gravity hot water and the pumped central heating made our decision.
The central heating system worked fine and the gravity hot water was also reaching the cylinder as the cylinder was up to temperature and the associated pipe work was also hot. The conclusion was that there was a blockage somewhere in either the domestic hot water pipe work or the cylinder itself. As the cylinder was badly corroded near the cold water entry point near the very bottom of the cylinder and the immersion heater was also not working and could not be removed we decided to replace the cylinder at the same time.
When we arrived back the next morning we drained the F&E tank that fed the cylinder and then added a missing isolation valve to the exit point of the F&E tank. As there was no drain cock installed in the cylinder we drained the cylinder by loosening the hot water flow connection on the top of the cylinder and syphoned out the water. Once empty we removed the primary coil connections and then cut the cold water fill pipe work at approximately the same height as the cylinder. The reason for that is that any remaining water (usually VERY black sludge) at the bottom of the tank won’t dribble out in the loft, down the loft ladder, the hallway carpets, the stairs, etc. When the tank was removed we could see that the blockage was being caused by the sludge in the tank. We ran some clean water through the hot water pipe work. It flowed well so we started to install the new tank. With some slight modifications to the pipe work the job was completed in quick time. We also took the opportunity to replace a frozen isolator tap while the system was empty. With everything filled and tested we cleaned up and were off to the next job.