Replacing a faulty valve

Replacing a faulty valve (control).

Control valves add flexibility and control to central heating systems, but if they are worn or faulty they can affect the reliability of the system and should be dealt with immediately. Harringay Plumbers can refit valves.

When you buy a new valve, to avoid modifying pipework, make sure it is one of the same pattern as the one you are replacing. Then, at your consumer unit, remove the fuse or MCB for the circuit to which the central heating controls are connected. The cable from the valve will be wired to an adjacent junction box, which is also connected to the central heating systems other controls. Take the cover of the box and disconnect the wiring for the valve, making a note of the terminals used, to make reconnecting easier. To remove the old valve, simply cut through the pipe on each side. When fitting the new valve, bridge the gap with short sections of pipe, complete with joints at each end. Spring the assembly into place and connect the joints to the old pipe, then tighten the valve cap nuts. Connect the valve’s cable to the junction box, then insert the fuse or MCB. A Harringay Plumber can fit all motorised valves.

Replacing the motor.

If the valve fails due to its electric motor then it should be replaced. There is no need to drain the system. Switch off the electricity supply to the central heating system, don’t merely turn of the programmer, as motorised valves have a permanent live feed. Once the power is off, remove the cover and undo the single screw that secures the motor. Open the valve, using the manual lever, and lift out the motor. Disconnect the two motor wires by cutting off the connectors. Insert a new motor, then let the lever spring back to the closed position. Refit the retaining screw. Strip the ends and connect the wires, using the new connectors. Replace the cover and test the operation of the valve by turning on the system.

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