No downtime during works or outages post project

Water quality significantly improved

The pump energy consumption reduced by approximately 60%

“The development was historically a real problem site, with repeated downtimes and customer complaints. Since the work undertaken by FairHeat, we have had no heating and hot water issues or complaints.”

Contract Manager, housing association


The client is one of the largest providers of affordable housing and care in England. The project is a mixed tenure development located in East London. The heat network consists of four tower blocks served from an on-site plant room. The equipment installed in the plant room includes gas condensing boilers, pumps, and an oil boiler.


The system at the development had been suffering from the failure of multiple boilers and pumps causing long term reliability and heat supply issues which were triggered by:

Poor water quality

The water quality was tested and found to have extremely high iron and suspended solid concentrations.

Flue installation

Collection and pooling of condensate in the flue was causing corrosion damage to the flue, leading to leaks.

Boiler issues

Boilers heat exchangers were heavily corroded and fouled due to the poor water quality, further exacerbated by poor sequencing and the large size of boilers resulted in cycling.

Works at the development were undertaken in an extremely congested plant room, with very limited space for boilers and severe access constraints. The development suffered from high running costs due to low loss header arrangement with the shunt pumps as well as high heat loss due to elevated primary flow temperatures.

A rapid design and deployment was required and the client, a housing association, engaged FairHeat to replace the failed boilers, pumps and flue system.

FairHeat Solution

FairHeat performed a review of the installed boilers and made a significant reduction of 33 % in boiler size. This helped alleviate access constraints and minimise boiler cycling by reducing the required boiler sizes. FairHeat used Veissmann boilers to enable the removal of the low loss header and boiler shunt pumps. The use of the manufacturer’s boiler sequencer reduced boiler cycling further and the boiler integral wheels assisted with manoeuvrability within the plant room.

The following remedial works were also undertaken:

  • Re-flushed system and installed side stream filtration to maintain water quality
  • Redesigned and replaced flue and condensate drains to maximise condensate removal
  • Reduced primary temperature from 80 °C to 75 °C
  • Used a packaged pumping solution to reduce onsite welding


The replacement was undertaken with no major downtime in heat supply to residents

Since the replacement works, there has been no heating or hot water outages for residents and all delivery issues have been resolved

The plant room is now operating with stable outlet temperatures and boiler operation

Since the re-flush and installation of the side stream filtration unit, the water quality is now at suitable levels and still improving

The pump energy consumption has reduced by approximately 60% saving around £10,000 per year in electrical costs alone


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