How Faulty Central Heating Installation Can Lead to Illness

A hidden leak in central heating can cause damp to accumulate and the growth of fungi to result.

One case of this problem involved a young couple in their late twenties who were both struck with allergic alveolitis and admitted to hospital at the same time.

Although the couple's conditions improved within 24 hours after the first admission, upon returning to their home the illnesses returned with greater severity. Their young child of only a few months old was unaffected however.

Questioning of the patients yielded no signs of a cause of the illnesses. For example, the most common cause of such an allergic reaction from exposure within a household, pets, was not applicable.

Upon investigation of the house to ascertain the cause of the problems, one of the first clues was that the expansion tank within the attic of the property was constantly being replenished. The expansion tank is a small unit partially filled with air which reduces the effect of pressure surges, known as water hammer, within the central heating system.

This constant recharging indicated that somewhere in the central heating system there was a leak. Thus fungal growth became the obvious suspect. However nowhere in the home could fungal growth be observed.

Settle plates placed within the rooms of the home showed heavy growths of fungi after incubation of a week, Spores within the home included species such as Penicillium Chrysogenum, P cyclopium, Dimorphospora sp, Epicoccum sp, Mucor and Aspergillus flavus.

The next step was to remove the floor coverings to try and find signs of damp or fungus.

The source was revealed to be entrance hall which had a wet mouldy lower flooring.

The underlying construction was then inspected and revealed a leak in the central heating system with heavy fungal growth present in the area. Air borne spore concentrations were high.

Serum collected from the patients was analysed using an enzyme linked immunosorbent assay (known as ELISA). This technique involves coating flat bottomed polystyrene microplates with fungal antigens. The patient serums were placed onto the microplates, along with 10 healthy control serums. The ELISA test showed that the patient serums contained antibodies from fungi species analogous to the antigens used.

In the test, the each fungal antibody is specific to a certain antigen, the antibody and the antigen bond forming a complex. The complex can then be detected.

The cause of the illness was eventually decided to be Penicillium (a common fungi found within their home) hypersensitivity.