Frozen Condensate Pipes

A Solution to Frozen Condensate Pipes on High Efficiency Boilers

The winter of 2009/10 was the coldest for years, despite all the talk of global warming. There were high snow drifts and low temperatures and this caused waht is becoming an increasing problem for homes with high efficiency condensing boilers - frozen condensate pipes.

Modern boilers produce as much as 1 litre per hour of acidic condensate. This is routed through a plastic drain pipe  which is often routed through the wall of the dwelling and in to an external drain. Horizontal runs should not be used because the condensate can build up and freeze inside the pipe.

During very cold weather, even with a good slope on the condensate line, the natural friction of the inside surface of the pipe combined with sub zero temperatures can lead to the whole lot freezing solid. At 1 litre per hour it doesn't take long to back up inside the boiler and trigger a safety switch which shuts the boiler down.

A kettle of boiling water is sometimes all that is needed, simply poured over the frozen condensate pipe but it's just not practical on a regular basis.

Oil Boiler Spares now stocks a range of 'trace heaters', special low power linear elements that are secured to the outside of the condensate pipe to prevent it from freezing. Available in 1-10m lengths in 1m increments, the kit includes everything except the 10mm insulation required to complete the job. Thermostatically controlled to switch on at 5°C with indicator lights to show what's happening and an RCD to ensure regulatory compliance.

These are available from our online store here.