Watret has a long-standing relationship with St Albans City & District Council, managing in the region of 6,000 properties in St Albans city centre and surrounding villages. The council required an upgrade to a selection of solar thermal systems within their housing stock.

Residents were reporting myriad issues with the generation of hot water from the current solar thermal system. The existing installations consisted of numerous manufacturers, many of whom were no longer trading.

Our initial investigation highlighted that the solar panels were no longer working effectively, with signs of leakage and weathering within the collectors. Other design issues were found; the drain back system had been incorrectly installed with insufficient head height and cylinders were twin coil copper design with low storage capacity.

We upgraded all thermal systems by fitting new collectors with pressurisation of the system through bespoke unvented twin coil solar cylinders which provided an increased capacity and greater temperature control. This consisted of providing a total Vaillant solution cleverly utilising the existing gas boiler. E Bus connectivity allowed all heating controls to be linked together providing end users with optimum efficiency.


  • Premium and improved system design that works for end users
  • 10 years manufacturer’s warranty
  • Long-term maintenance agreement
  • Cost savings



CLIENT: St Albans City & District Council

PROJECT: Marford Road Solar Upgrade

VALUE: £92,000

PERIOD: 8 Weeks 2016

16 solar thermal systems over 8 week period
Smart eBus energy efficient controls
EPC, MCS registration and commissioning