Our customer bought a large house near Ashford Kent, in a rural setting. They knew the property needed a lot of work, the previous owner had dedicated his life to refurbishing it, and to be frank, there was an awful lot still to be done when he handed over the keys.
This was a refreshing refurbishment to be asked to get involved with; our customer had read this blog from time to time, and we were on his list for this project before we knew about it.
Unlike some customers, who would buy a large property, have it completely remodelled by a firm of City based architects, and move in two years later, our customer moved in on day one and intended to work through the house in their own time, doing much of the work themselves. The wife was often at the top of a scaffold tower painting the windows, before their children had to be picked up from school.
We could tell you about large areas of floor needing propping up, water leaks etc, but at the end of the day this blog is about heating.
There was a Grant Vortex 30Kw oil boiler in the basement on a sealed system, which was connected to some of the ground floor radiators. This had a very dodgy looking vertical open flue attached, which mysteriously terminated horizontally above the 1st floor. There was a Merlin 50Kw oil boiler on the ground floor which did some of the rest of the house plus two HW cylinders.
And then there was an old Rayburn wood fired stove that did another HW cylinder and around 8 radiators in another wing of the house. This part had apparently formerly been connected to the Merlin oil boiler but a tenant had been taken on, and the services separated.
Oh, and the oil tank was a 3000 litre unbunded steel unit, which was showing signs of weeping on the corners, so was scrap. It was perched on stilts suggesting an AGA might have once been involved, and was resting against the wall of the house. There was also a tenanted part of the house linked to the main heating system.
The survey for this job took a bit of time, as you can imagine. Our customers, who knew a fair bit about heating systems (and house renovations, luckily) where quite keen on having a single boiler room, and had already decided that they wanted to zone the heating in the house.
So the first question we considered was, what fuel source? If both the oil boilers were scrap, and the tank was finished, this meant that alternatives could be considered without wasting anything.
Whilst there was enough land for a ground source heat pump, these don’t work very efficiently in an old building with poor insulation and no real prospect of installing underfloor heating. We have seen a couple of very large older properties where owners were taken in by the ground source heat pump story peddled by ‘property journalists’ that were taken in and not technically proficient to understand the issues. In some cases the running costs have led the Ground Source systems to be disconnected.
So this left Oil versus LPG. LPG (Liquid Petroleum Gas) can be considered similar to Natural Gas (although it has a different molecular structure) and unlike the latter, for rural sites it is delivered in liquid form on a tanker. The LPG supplier typically also owns the tank and is responsible for the safety and upkeep of the supply, all the way to the edge of the property, in the same way that a town dweller is responsible for their Natural Gas installation beyond the gas meter.
LPG tanks have to be installed within line of site of the tanker, and the siting distances from boundaries and buildings are more onerous than for Kerosene oil tanks. They can be sited above ground, or below ground, buried under the garden.
Our customer chose Calor as his supplier, and after a considerable delay due to a shortage of commercial sized buriable tanks, a large hole was dug and the tank craned in. For the intermediate period we had hooked up 8 large temporary cylinders.
The Rayburn fuel burning stove was disconnected from its radiators, and these were repatriated to the original heating system pipework.
When we removed the Rayburn wood stove (installed by the previous owner) we uncovered some defects which could have resulted in a serious fire.
The small ground floor boiler room formerly containing the Merlin Kerosene boiler was stripped out and two Worcester Greenstar 8000 LPG system boilers were installed in a cascade, linked to a header mixer.
The boilers could be used to power the rental flat area, or the main house, or both, using separate subcircuits.
A Tekmar cascade controller was used to sequence the boilers and intelligently ramp them together or run the boilers separately.
It was a lot of equipment to fit in a small room, but it was achieved.
Many of the old panel radiators were swapped for iron school type radiators in the reception rooms, some of which were very large. The main lounge for instance, formerly had a music licence for 260 people.
The house was divided into 24 separately controllable heating zones, using the fabulous Honeywell Evohome – plus the rental area which is controlled separately.
The 24 zones of heating allow the heating bills on a vast property to become manageable. And of course enable those rooms being used to be comfortable, rather than keeping a thermostat turned down for the whole house.
The boiler system, which was installed in late 2019 (it takes me while to catch up with case studies), came with a 12 year Worcester warranty on both boilers.
At the annual service in late 2020 our customer reports massively reduced running costs compared to those endured by the previous owner. You can read their review on Google!