Help! Worcester combi keeps bursting plastic heating pipes! 10yr old 24i combi in 10yr old caravan has been troublesome for the past 4 years or so and although I have had a service contract I cancelled it as I have no confidence in the engineer. Boiler has had numerous PCBs replaced and after the last replacement last year, two pipes in both the heating circuit and hot water circuit burst with LOTS of steam. Worked OK for a while after repair but at the beginning of this season another heating pipe burst about 15mins after starting up following winter storage (antifreeze had supposedly been checked). Lots of vibration and rumbling a few seconds before letting go! I noticed the pressure fluctuating between 1.3 and 1.7mbar before the burst. Overheat trip used to trip out a few years ago but hasn't done it since it was 'fixed'. Boiler setting had been on mid position but reduced to minimum about 5 mins before the blow. Any ideas? Is it safe?
