my heatline combi boiler,had a leak,phoned ins,they sent engineer out,he said it was the heat exchanger,waited for part,he replaced it,went away,3 hrs later,bedroom and kitchen flooded,got other engineer out,he thought it was same problem but found it was the plastic o ring on the flow switch had gone,problem sorted but i,m left with sorting damage out,we both pensioners,so the ins want us to pay £350 excess,can any 1 help.me to sort this out,who was responsible ?please any help gratefully apreciated thank you john,plus it looked like seal had gone on heat exchanger because water from o ring was hitting heat exchanger and spurting off,but when engineer first replaced the heat exchanger,the o ring must have broken off more,i.e causing a bigger volume of water to escape,Sorry if i never exp properly.reason it never caused more damage was,i turned all water suply off to boiler,as soon as wife found towels wet underneath it,it was only when 2 engineer fixed,wat he thought was problem,that water was turned back on,then when he went,my son noticed that the needle was on its lowest so he just filled it up with filling loop,and left it,then thats when the water escaped