Coolers and Condensers Ltd were asked to replace a dry air cooler on the roof of an internationally renowned teaching hospital, but there were a few challenges to overcome. The original unit was put in some 25 years ago on the roof of a 7-storey building. Over time additional buildings were erected around it which meant it was impossible to crane a new unit onto the roof, and air lifting a new unit was out of the question. It was impossible to re-position the unit elsewhere, so a re-build was the only option. The unit was 7.2 metres long but the only way to get it to the roof was in a 2.5m deep lift. In the end we designed multiple coil blocks to fit within the lift which were then assembled and brazed together. There were almost 5000 brazed joints on the unit, all done when the coils were in position. Once fully brazed and tested the casework was replaced and new panels added where required. The headers were re-connected and the unit ran as when it was new. The complete project took around five weeks on site.