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How to diagnose an impellor problem?

How to diagnose an impellor problem?

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Image showing a failed pump that is covered in sludge If your boiler pump fails, then it’s possible to check whether or not there is a problem with your impellor, using your boiler pump multitool.

What is an impellor?

Image of an impellor An impellor is a rotating cylinder with angled slats on both its flat and curved surfaces..
Diagram to show how water is sucked into an impellor and then forced back out, causing it to flow around a central heating system These angled slats draw water into the cylinder as it spins and push it back out through the sides, causing water to circulate around your central heating system.

How to find out if your boiler pump has failed because of the impellor

Image showing a DIYer turning off the electrical power supply at the fuse box

Step 1 – Turn off power

The impellor is one of the components of your boiler that could have broken down if your pump is no longer working.

First, turn off all electrical power to the boiler and make sure it cannot be accidentally restored.

Image of gate valves either side of a boiler pump

Step 2 – Protect against water damage

Use the gate valves either side of your boiler pump to cut off the water supply using grips or pliers.

Image of a stack of towels ready to be laid down to prevent water damage to a DIYer's flooring Put down towels to protect flooring or electrics.
Image of a DIYer unscrewing the bleed screw cover plate on their circulator pump using a boiler pump multitool

Step 3 – Detach bleed screw cover plate

Remove the bit that is currently in your multitool’s bit holder.

Using the long, flat bit located on the multitool’s handle, completely unfasten the bleed screw cover plate by twisting the tool anti-clockwise.

Image of water leaking out through the face of a boiler pump head

Step 4 – Check for water

Check to see if water pours out.

If water pours out…

Headstone for a dead boiler pump If water pours out of your pump then the bearings have worn out and your pump will need to be replaced.
Image of a young, up and coming DIYer who is keenly mopping up the spillage from checking the impellor on their boiler pump Replace the bleed screw cover plate and mop up any spillage.
Wonkee Donkee reassures the DIYer that they will be provided with guidance about changing their boiler pump

If water does not pour out…

Image of a 4mm flat screwdriver bit If only a small amount of water comes out of your pump, there’s still hope!

You’ll need to insert the 4mm flat screwdriver bit into your multitool’s bit holder.

Image of the slot that you use to turn the impellor shaft with a 4mm flat bit screwdriver head You should be able to see a slot into which you can insert the multitool. Once inserted, gently turn the tool anti-clockwise.
Image of a DIYer straining to turn a jammed impellor If you cannot turn the impellor shaft anti-clockwise, or if it grinds when you turn it, you will need a new pump.
Image of a happy DIYer who has just discovered that the impellor in their boiler pump is working again If it turns anti-clockwise freely, then you’re in the clear! The impellor was probably jammed with particles of limescale or other debris, which you have just dislodged by turning the shaft.
Image of a DIYer experiencing electrical problems with their boiler pump If the impellor shaft turns freely when you test it, but the pump will still not run when you replace the cover plate and switch it back on, you may have an electrical problem with your boiler or a more serious problem with your impellor. Your pump will need to be replaced.

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