Hi guys, hope you can help me out. My dad has just rang me as he has been having issues the central heating in his house. What I've managed to get out of him is that the boiler has been tripping to overheat every evening and the pump keeps running even when the system is off (thermostat). I told him to drain the system and run some fernox through it but my knowledge when it comes to this stuff is very limited. Any suggestions?