Should you ever have to change the circulating pump in your central heating system a good routine is to do a couple of basic checks before you remove it. This means checking and noting down the direction of flow markings on the pump and pipework, also make sure that the replacement is exactly the same as they can vary. Always try and take as much detail as you can, even take photos. Note: If you are taking it out for some other reason, then label all connections so that you can re-fit afterwards. A South East London Plumber can identify, supply and fit a central heating pump. Turn off the power to the central heating at your consumer unit to ensure the direct electrical feed to the pump is off as they are nearly always directly fed with a constant live supply. Shut the spindle operated water valves either side of the pump. These pumps can only spin in one direction and have a flow arrow marked on the casing to help when the pump is being installed or replaced (as stated earlier). If you are not confident call an expert. Disconnect the electrical power on the pump by unscrewing the cover of the terminal box which is normally fitted on the side of the pump. Use an electrical tester to confirm that there is no voltage at the terminals. South East London Plumbers can fit and commission new pumps. There is also a dial/screw fitted on the pump case, so that the pump speed can be adjusted manually. When disconnected, undo the nuts on the pipe and remove the pump. Carry out the work and replace in your own time. Note: These motors are very quiet runners. They do vibrate when running. A large screw on top of the pump is the bleed screw and is fitted to allow any air in the pump to be bled. Central heating pumps do not self-prime. So any air inside cant leave until it is bled out at the screw. Loosen the screw slowly until the hiss (air) stops and then tighten back up again.