These appliances employ a catalytic converter which is a ceramic honeycomb, coated in platinum sponge. The exhaust gases pass through the honeycomb. If a carbon monoxide molecule (C0) touches the platinum sponge it sticks. When another C0 molecule hits it, it is released as C02.

As usual the products of (complete) combustion are C02 and water vapour. Following FGF manufacture C02 is around 4% and C0 around 5-15 ppm. Normal ventilation takes care of the innocuous products of combustion and a 50 square centimetre permanent vent is required. It should be borne in mind that any habitable room includes a requirement for up to two air changes per hour.

A minimum room volume of 40 cubic metres is required for the larger input FGF units. The new range of smaller input FGF units require a minimum room volume of only 30 cubic metres, in addition to the permanent air vent. As with all gas appliances there are the usual common sense rules for installing appliances away from combustible materials, which is covered by MI.

I have noticed with more than one conventional OF gas fire under 7 kw, manufacturers instructions suggest permanent air for combustion may be required, given the modern trend in favour of draught proofing and accurately fitting double glazed windows. Adventitious allowance should not be taken for granted.

The catalytic converter (CC) is only guaranteed for two years but it is normally expected the CC will survive the life of the appliance. It is also claimed units have been on test for 20 years with no sign of deterioration. If the FGF had a poor record in this respect it would not have survived long enough in my view to enjoy a population of 8 million in the USA. These appliances are fitted with an Oxygen Depletion Sensor like all modern gas fires which kicks in when the oxygen level drops by around 2%.

Annual servicing is relatively simple and you will need the technology to test combustion levels. Following the usual checks associated with gas and Manufacturer’s Instructions it is recommended the appliance is run on full for not less than ten minutes and a test made for C0. If C0 exceeds 30 ppm the catalyst will need replacing.

FGF stoves were never cheap at around £ 800 .00p but the new range of inset gas fires with 2.4 kw input are competitively priced at around £ 449 .00p. FGF cannot be fitted in bedrooms, bathrooms or basements.

These appliances are of course 100% efficient, unaffected by fans of any type, including overhead fans and have the additional benefit of filtering many odours normally found in the home. Models are available in natural gas and LPG.

The manufacturers, Burley, will soon have Manufacturer’s Instructions on line and can offer in-house product training.