Moved into newish house, have a Powermax 155. It wont light the burner and keeps locking out. I have tried most of the yellow pages to get a plumber to come and look at it, those that i have spoken to will not touch it with a barge pole. So 2 questions, is the boiler really that bad that i should think about ripping it out and starting again? and can i open up the boiler and have a go at fixing it myself. One plumber mentioned that it may be a drop in pressure that can be rectified by fiddling with a black \\\"hose type\\\" thing at the bottom of the unit - advisable or not?