How to Change the Feed Pump for Boilers

Turn off the electrical supply for the boiler at the main circuit breaker. Allow the water inside the system half an hour or so to cool down.

Use a radiator key or wrench to loosen the radiator bleed screws on the radiators located furthest away from the boiler.

Turn off the cold water supply valve for the boiler. These are usually situated above the main boiler body. The handle may be labelled or colored blue to indicate the cold water feed. Rotate the valve or knob in the direction indicated on the valve or pipe to cut the supply.

Drain the central boiler system. The exact steps for this will depend on the configuration of your central heating. Most modern systems will have a single drain point consisting of a shutoff valve. This valve may be located on the outside or in the basement of your house. Open the valve and allow all the water inside to drain out. Close the valve once the system is drained.

Remove the service cover for the boiler by loosening the screws or bolts at the sides. Lift the cover off the boiler and set aside.

Locate the feed pump. These are typically cylindrical in shape and can be identified by the water supply pipes leading in one side and out the other of the pump. There will also be a series of wires, either connected separately to terminals or in a wiring harness.

Disconnect the pump wires. For terminals, loosen the terminal screws and pull the wires out of place. For pumps with a harness, gently pull the plastic wiring harness plug out of the pump body.

Loosen the inlet and outlet pipe couplings at either end of the pump body with a wrench. Hold a towel underneath the feed pump body as you do this, as a few drops of water may spill out.

Loosen the bolts holding the pump body to the boiler casing with a socket wrench or wrench. Pull the pump out of the boiler.

Wrap the threads on the end of the pump with plumbers tape. Use scissors to trim off any excess.

Insert a new pump into the boiler body and slip it into the pump socket. Secure with the pump bolts.

Reconnect the power wires to the pump terminals or plug in the wiring harness.

Replace the boiler service cover and secure.

Open up the cold water supply valve. Keep an eye on the pressure gauge and cut the supply valve when the valve reads that the system is at the correct operating temperature.

Restore power to the pump at the central breaker.

Bleed the system as needed to restore the correct system pressure. Hold a towel underneath the bleed screws. Open the bleed screws until water starts to drip out. Close the bleed screws. Top up with more water by opening the supply valve if needed.