This is a house in a remote location near Maidstone, Kent. Some 200 years old, it was bought in a semi derelict condition over 35 years ago by the present owner, whose late husband was an architect. He remodelled and partially rebuilt the house, retaining all the period charm, but incorporating modern upgrades, including adding ducted warm air heating.
The heating plant room was around the back of the house in an external cupboard, and the original warm air unit (oil fired) was replaced around 14 years ago by a local contractor. This 1990s unit, a Lennox oil fired cabinet, had been giving problems and some parts were no longer available. Lennox no longer supply new oil warm air in the UK.
My initial inspection showed that the Lennox unit had not been installed by a bodger, with the ductwork modifications comprising mainly duct tape and some poorly shaped aluminium panels – there was air leakage from all areas. The boiler flue was jury rigged from pieces of cement flue, rigid steel sections and around one metre of exposed flue liner, including a draught diverter which was blown outwards and discharging much of the combustion products directly into the boiler room.
Where they were sucked in by the many holes in the ductwork and distributed around the house. The oil fire valve and filters were not screwed to the wall in the traditional way, but each resting on a loose brick on the floor.
Our customer also had an indirect hot water cylinder inside the house, which was heated by electrical immersion heater. They desired a system, run on kerosene (oil) as before, which could do warm air and heat the hot water quickly.
For this application we designed a system around a new high efficiency Worcester-Bosch Camray Greenstar external oil boiler. This would create around 30Kw of power in the form of heated water. There wasn’t room for this and the warm air equipment in the cupboard, so we specified an outdoor unit.
A top spec air handling unit containing a water heat exchanger matrix was installed in the air ducting, all the more recent alterations were scrapped and returned to a professional quality fit out by our skilled ductwork contractor, Dave.
The hot water cylinder was also connected to the new Worcester Bosch boiler, to give a very fast heat up and a full 180 litres of useful hot water, unlike the 27″ electrical immersion heater, which used to heat only the top few feet of the cylinder.
Air Handling Units are commonly used on commercial installations for air heating and cooling applications. Think of them as a big box with a fan, and a large car radiator inside. When we need to heat the air in the house, a water boiler (in this case, the Worcester Bosch condensing oil boiler) heats the Air Handling Unit’s internal high efficiency finned radiator with circulated water. The fan starts, and, within moments, the house is getting warm via the original ductwork.
Of course, there is a little more going on in our air handling unit, in this case the MultiCalor MC30.
This unit is heavier than the whole oil fired warm air unit that came out, and is so quiet it can hardly be heard. It features a super quiet and efficient roller bearing fan, which is driven by a sophisticated inverter, which automatically varispeeds the airflow based upon temperature sensors fitted internally.
It takes warm air to the next level, domestically.
The system was commissioned and our normal 5 year Bosch warranty given on the boiler. Honeywell radio controls were fitted in the form of a CMT927 programmable thermostat, just like a radiator system.
We are shortly commencing another Worcester Bosch powered MultiCalor installation; this one is a house where the warm air system dates back to the 1960s, but the house has been extended over the years, and because warm air ductwork is not easily extended, electric night storage heaters were fitted in the new areas. Unsurprisingly, our customer finds the night storage heaters to be both expensive and useless, so we are fitting radiators in the newer parts of the house. One high efficiency boiler, one air handling unit, 10 radiators. More follows in a later post. You saw it here first.