Laurence Deacon Court – Plant room upgrades

Laurence Deacon Court is a development of five sheltered housing units with 70 one and two-bedroom apartments and bungalows. Some of these are mobility standard properties. Built-in 1981, it is operated by Alpha Living, a not-for-profit housing association that focuses on independent living for the over 55’s. They have over 860 apartments across 11 local authorities. For the residents, they have the benefit of their own space and front door, but also shared spaces open to all residents and regular social activities. It’s independent living, but with a helping hand.

When they were first built, each of the individual blocks had two cast iron Hamworthy Purewell boilers @ 85kW each. These have served them well over the years. With regular planned, preventative maintenance, they have been reliable but were at the end of their usable life. With an operating efficiency of 50% or below when new, they were proving extremely costly to run.

There were a number of significant challenges in the job. The first of which was the threat of asbestos lining in the plant rooms. With a specialist drafted in to check, this proved not to be the case. The second challenge was keeping the residents warm and with access to hot water throughout. We brought in our own temporary boilers, that were connected into the system before decommissioning the old one. We then worked sequentially, moving from block to block, to replace each of the systems in turn. The third was the scale of the plant rooms, which are tiny and made working on-site a challenge in its own right. All of the old plant had to be removed, before we could even think of installing the new.

The overall project took only 15 weeks in total however.

Each plant room is now fitted with two 90kw Potterton Sirius units. These operate at 97.3% seasonal efficiency and 87.7% overall, so will show an immediate saving in running costs. They are supported by new and more efficient A-rated twinset pumps. Each apartment has its own small hot water cylinder that’s fed from the boilers. With the old system, the whole 170kw capacity of the boiler would need to be fired up to top up the hot water tank when some is used. With the new system, it modulates between the two boilers and only fires up as much capacity as is needed. This can be as little as 20% capacity of just one individual boiler, that modulate in turn to prolong life. With these figures, it is clear to see the potential savings, with both the efficiency of the new boilers and their ability to only deliver what is required as it is demanded. Bills could reduce by well over 50%. Even with the current gas price hikes, there is potential for a huge ongoing cost reduction and will make the payback for the upgrade far, far faster.

In each of the plant rooms, the stack was relined with stainless steel flue liners with solid stainless steel cascade headers, the systems were pressurised using pressurisation units with flood alarm facility. Boiler interlock systems were installed to comply with current building regulations with thermal links above each appliance.

As our work was in the plant rooms and not the individual apartments, we also completed a full freshwater system flush, added magnetic Air/Dirt separators and added inhibitors to the system, to ensure a long life and reduced ongoing maintenance.

With the systems fully commissioned, working with Potterton, we were able to offer a five-year breakdown cover on the boilers as long as the correct maintenance procedures are adhered to.

With gas prices being of such concern, the ability to remove such a large percentage of ongoing running cost is one that is making more and more financial sense. We have written about these ongoing savings in the purpose-built student accommodation (PBSA) sector and the arguments for upgrade for ongoing savings are exactly the same in the sheltered housing sector. Payback can be as little as 3-7 years depending on quite how inefficient the old system is.