After checking for issues with your pump, you may have discovered a problem with your impellor, or there may be a problem with the pump’s electrics. Either way, if your pump isn’t working, you may find yourself needing to change it.
It’s possible to change the whole boiler pump but this guide specifically deals with removing the boiler pump head.
It’s unusual for there to be a problem with any other part of the boiler pump and this should be a quicker and easier way to solve your boiler problem.
What is a boiler pump head?
A boiler pump head is the ‘business end’ of your boiler pump. It houses the impellor, which is the part of the pump that makes water flow around the central heating system. The rest of your pump assembly is really just an extension of your pipework.
Removing and replacing a boiler pump head
Step 1 – Turn off power
Make sure the power is switched off at the fuse box and cannot be accidentally reconnected.
Step 2 – Protect against water damage
Turn the gate valves either side of your boiler pump to cut off the water supply using grips or pliers.
Put down towels to protect flooring or electrics.
Step 3 – Open bleed screw cover plate
Remove the bit that is currently in the multitool’s bit holder.
Use the flat bit mounted on the handle to unscrew the bleed screw cover plate, twisting anti-clockwise.
Step 4 – Check water
Any water that was in the pump head should leak out. This may be a trickle, or it may come a little faster depending on the problem that you’re experiencing with your pump.
If the water is black, or if it contains debris, you will need to drain your central heating system.
Keeping the water in your central heating system free of debris like this is important because it prevents the formation of sludge, which can make your radiators run cold at the bottom, or clog up your pump.
Leaving debris in the system could also damage the new pump head you are about to install.
Step 5 – Remove pump head
Fit the correctly-sized allen key bit into your boiler pump multitool. Only one of the available allen key bits will fit into hexagonal indentations in the retaining screws so it should be easy to work out which is the right one.
Unscrew all four of the screws holding the pump head in place.
Remove the pump head and set it aside. It may be wet and dirty, so avoid putting it on any surfaces that could stain.
Step 6 – Check rubber gasket
Now that your boiler head has been removed, you can check the rubber gasket that sits in the part of the pump that attaches to the base of the motor that drives the impellor. If it is broken (like a snapped rubber band), pull it out and discard it.
Replace it with a new rubber gasket. Make sure it fits snugly around the inside of the volute as this will create a seal and prevent leaks.
Step 7 – Install new pump head
To fit a new pump head, all you need to do is line up the bolt holes and screw it onto the part of the pump assembly that’s still attached to the pipes.
Switch the water back on. Leave the central heating system to refill if you drained it.