After reading a reponse to another question, I think the problem with my boiler is a blocked condensate trap. The boiler seems to not work whenever there are days of heavy rain. How do you repair a blocked condensate trap and does it have to be done by a qualified tradesman?

caroline langford, November 2010

boiler condence traps have a plug or are removal to clean out, however can be difficult, and blockage is often on drain pipe after trap often at point it joins main drain. warning if you clean trap, refill it with water before firing boiler, or fumes with exit via drain. water trap stops them and they exit thru flue outlet

deano, November 2010