I have a worcester 240 combi RSF boiler. Over the last few months i was having to top up the pressure manually with the tap on the silver braided pipe, about once a week to keep it at 1.5 bar. Now that its colder and the boiler is being used constantly the pressure is dropping down to 0 bar every 2-3 hours. I've checked for leaks on the rads and found none. I have noticed a small drip of water on the bottom grill of the boiler casing sometimes but can't see where its coming from. Also there is a bent copper pipe coming out of the wall directly behind the boiler and it drips constantly (is this the pressure relief pipe?). Its dripping cold water though, would that still be from the boiler? would this amount of pressure loss definitely be a huge amount of water or could a drip cause it??