Any good tips on keeping a condensate pipe from freezing on a worcester 24i. The inlaws have had BG out twice now and all they do is pour hot water down the pipe, then leave. The system is on a 3star 24h contract, but BG cant get back till tomorrow evening, and even then i think he will only defrost the pipe again. I have noticed that when the pipe goes through the outside wall it has a slight upward slope, ie no fall, will this only add to the problem. I have had the hairdryer on the pipe to get it running again, and also removed the bottom pipe connection on the boiler so that the condensate can run out of the tank and into a temp container. But any good tips on KEEPING the pipe from freezing would be much appreciated