Help CentreDuring winters the UK has experienced prolonged spells of extremely cold weather – down to minus 15°C in some areas. This resulted in a significant increase in the number of calls to boiler manufacturers and heating installers from householders with condensing (high efficiency) boilers where the condensate drainage pipe had frozen and become blocked with ice, causing boiler shutdown. In the vast majority of cases, problems occurred where the condensate drainage pipe was located externally for some part of its length.
Due to the cold weather our ATAG boilers can show a fault code 133 or 501(No flame after 5 attempts) due to the condensate pipe freezing, as a result of the condensate not being able to run away from the boiler and the boiler to eventually come up with a fault code 133 or 501 due to that fact.
The condensate pipe can be thawed by applying a hot water bottle, a microwaveable heating pack (the sort used for muscular aches and pains) or cloths soaked in warm water to the exterior of the pipe, close to the likely point of blockage. Warm water can also be poured onto the pipe from a watering can or similar container. Do not use boiling water. Note: You should not attempt to thaw a condensate drain pipe if you cannot easily reach it from ground level. Be aware that any water used can quickly freeze if it falls onto pathways – causing a possible slip hazard.
In most cases, once the condensate drain pipe is cleared and a reset has been carried out, the boiler will re-ignite using its automatic operating sequence.