We were approached by our client to help solve a problem they had with their existing Air Source Heat Pumps. These were positioned on the roof of a commercial building in Scotland and designed to provide hot water for the building.


Their original contractor had installed two 60kw Air Source Heat Pumps in 2010 but since then the client had suffered from repeated compressor failure, coil bursts and complaints of vibration noise through the buildings top floors.

Following a site visit, we determined that the reasons for these problems were that the units had been incorrectly installed. The Air Source Heat Pumps were sat on concrete paving stones, directly onto the flat roof, which had a slight incline of between 10 to 15 degrees. However, the units had not been placed in a level position meaning that the water couldn’t run away effectively. This had led to an excessive ice build up on the coils which then resulted in parts of them becoming crushed, together with oil and refrigerant leakage which subsequently resulted in compressor failures.


Having examined all of these issues, we explained to our client that the solution lay in ensuring that the Air Source Heat Pumps were correctly installed, taking into account the slight incline of the roof and vibration control.

Our client expressed their wish not to spend any more money on trying to repair them, as there would be no guarantee that the coils would not keep failing.

Our solution was to strip down one of the units and rescue any parts that we could to use on the other unit, together with purchasing one new unit. We then reinstalled the existing unit as well installing the new unit, both with new pipework.

Most importantly, both were placed in a level position with anti vibration mounts on new made to measure frames with angled (wedged shaped) anti vibration feet. This eliminated the angle of the roof and allowed the water to run away from the condenser coil before icing up the coil and causing damage, together with the anti vibration mounts eliminating the vibration through the building.

In order to position the units on the roof, a crane was needed to lift them into position. As the main contractor on this project, we had full responsibility for overseeing this together will all health and safety requirements including traffic control.


We are glad to say that the result was two fully operational working Air Source Heat Pumps which provided hot water to the building successfully and a happy client!