Ian Byrne An early Condensing Boiler

The National Energy Foundation has recommended installing high-efficiency gas condensing boilers since they were first introduced onto the UK market.  So, when the boiler in my home failed soon after joining the Foundation in 1991, I decided to fit one myself.  At the time there were only three brands available on the UK market, and I chose a French design as it was the only one certified for a vertical flue (ie. up the existing flue from my boiler location situated in a small utility room without an external wall).

The boiler was fitted and ran well and reliably from the very start.  At first some of my neighbours commented on the steam from the top of the flue in cold weather, due to the lower exhaust gas temperature; now they all have condensing boilers of their own and it's no longer remarkable.   The boiler was also initially fitted without a room thermostat as it relied solely on thermostatic radiator valves (TRVs) to control the room temperature, in accordance with Government advice at the time.  This was a mistake, and after a couple of years I bought an internal weather compensation room thermostat.  This control simply delays switching on the central heating system on days when the internal; room temperature is already quite high, with a range of about 30 minutes.  So by setting the room to be at a comfortable temperature for (say) 8 o'clock in the morning, it will adjust the heating start time from 7.30am to 8am.  This took a little getting used to, and we still needed to use the override if we had been out and wanted heat on instantly, but did help us keep our bills low.  Our gas bill was generally around half what was quoted for a normal house of the same size and built form.

Condensing boilers are sometimes criticised for being complex and unreliable.  That certainly wasn't our experience and, with regular servicing, we got over 15 years use, with the only problems being the fan occasionally stopping in a "dead" spot and needing a manual flick to re-start.  However eventually the electronic fan controls (or possibly the fan itself) failed, and as the importer of the boilers had gone out of business and out installer had retired, the simplest solution was to replace the boiler with a more modern model.  (In theory we could have bought a replacement kit of parts from the French manufacturer, but would then have found it hard to find a competent installer.)