The Challenge

A modern 50+ apartment development in Croydon (completed c.2020) was experiencing repeated issues with its low carbon communal heating system. Residents were dealing with intermittent heating and hot water outages, driven by significant air locks within the distribution pipework serving all apartments.

When DMG Delta first attended site, the lack of “as installed” drawings made it difficult to trace the pipework layout and identify key venting points. The system had likely been drained down before our involvement, allowing air into the pipework and affecting the network hydraulics. This caused:

• Repeated air locks
• Flow imbalances between blocks
• Reverse circulation, where one block’s pump overpowered another and pushed water in the wrong direction

As we investigated further, it also became clear the system didn’t have a structured water treatment regime in place to protect system assets and maintain efficiency. Water quality was found to be substandard, with high dissolved copper, which may have contributed to the failure of a boiler heat exchanger.

Our Solution

Following an initial exploratory site visit, our technical engineering team set out a clear plan to stabilise services and correct the underlying causes:

• Replaced multiple automatic air vents across the site to expel trapped air and reduce recurring air locks
• Monitored and balanced pump speeds using specialist flow rate equipment to correct reverse flow and restore stable circulation between blocks
• Flushed and chemically cleaned the system to improve water quality and protect plant equipment
• Diagnosed boiler damage and arranged for a replacement heat exchanger to be fitted.

Throughout the works, the team took a methodical approach and kept services running wherever possible. Even without original commissioning records, our engineers combined practical experience with on-site testing to rebuild an accurate picture of how the system was behaving and then bring it back into balance.