I thought I remember reading in some tv mag that Kirsty sabotaged the boiler.
But haven't seen any evidence of this. Does she know about Tyrone and Fizz and is keeping quiet?
No, she didn't touch the boiler - there was a problem with it and Tyrone tried to fix it.
Fizz had a problem with her sewing machine at work - Julie turned the power off whilst Fizz found out what was wrong - Kirsty switched the power back on - result : nasty hand injury to Fizz. This might be the incident you're thinking of.