So i discovered, last night, that my Baxi back boiler had stopped working at some point during the day (no hot water). On closer inspection, the pilot light fails to stay lit when I let the button out so I presume the thermocouple has failed :/ I decide that it's not an emergency, what with it being summer and the fact that I have an immersion heater to see me through until I can get a gas engineer to fix the boiler. I try the immersion for a few minutes last night (I've never used it in the 9 years I've been here) and it pings quietly and cracks a bit so I presume it's ok, turn it off and go to bed. This morning I turn it on and leave it on only to hear a loud pop / bang and on opening the airing cupboard door, I'm greeted with an electrical burning smell I guess it failed then... So here I am trying to find a gas engineer to fix my boiler at the same time as trying to find out how to swap the immersion element. It doesn't look like a hard job but there are some pitfalls, e.g. twisting the thread mount right off the tank! Does anyone have any hints and tips when it comes to changing the element? Thanks. e: it's a top mounted element so do I need to drain the tank or can I get away without doing that?