Replace a uPVC door multipoint lock

Learn how to measure, buy and fit a replacement uPVC door multipoint lock safely, testing it before closing the door.

DL-01Measure the old lock before you buy a replacementOpen the door and measure the backset - the distance from the edge of the door to the centre of the cylinder hole, usually 35mm or 45mm. Measure the lock case length from screw to screw (common sizes are 92mm, 108mm, 200mm and 215mm). Note the PZ measurement too - the distance from the centre of the spindle hole to the bottom of the faceplate, usually 92mm. Take these measurements and the old lock's brand name to a locksmith or hardware shop, because multipoint locks are not a universal fit.

1 each · Tape measure

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DL-02Gather tools and protect the areaLay a dust sheet under the door to catch screws and debris. Get a Pozidriv screwdriver, a flathead screwdriver, and some light oil ready. If your door is heavy or the frame is tight, line up a helper before you start.

1 each · Dust sheet

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1 set · Screwdriver set (Pozidriv and flathead)

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DL-03Support the door before you remove anythingA uPVC door can weigh 40kg or more, and it can twist if left hanging with the lock out. Prop it open with a door wedge, or lift it off its hinges and lay it flat on a padded workbench or two trestles. Get a second person to help lift - do not do this alone.

1 pair · Door wedges (pair)

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1 each · Moving blanket or padding

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DL-04Remove the handlesUndo the two long screws that pass through the handle backplate on the inside face of the door. Pull both handles away from the door and set them aside. Keep the square spindle bar that connects them safe - you will need it again.

DL-05Remove the cylinderFind the single screw on the door edge, roughly in the middle of the lock faceplate, that holds the cylinder in place. Undo it, then turn the key about half a turn to disengage the cam and pull the cylinder out from the outside face. If it's worn or you've lost keys before, now is a good time to replace it.

1 each · Replacement euro cylinder

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DL-06Take out the old lock caseRemove all the screws along the faceplate on the door edge. Slide the whole lock case sideways out of the door edge - it can be a tight fit, so work it out gently rather than forcing it. Check the shape of the recess and faceplate cut-out so you can match the new lock to it.

DL-07Fit the new lock caseSlide the new multipoint lock case into the same slot, lining the faceplate up with the recess. Fit the top and bottom faceplate screws loosely at first so you can still shift the case slightly. Refit the cylinder and spindle before you tighten anything fully, so you can check the key and handles turn smoothly.

1 each · uPVC multipoint lock mechanism (matched size)

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DL-08Refit handles and cylinder, then test with the door openPush the spindle through and refit the handles, tightening the backplate screws evenly on both sides. Refit the cylinder and its retaining screw. With the door still open or off its hinges, lift the handle to check the hooks and rollers extend, then turn the key to check the shootbolts throw. Sort out any stiffness now, while the door is still off or open.

DL-09Rehang the door and check the keepsIf you took the door off, rehang it on its hinges with a helper supporting the weight. Close it gently and work the handle and key to see whether the hooks, rollers and shootbolts line up with the keeps in the frame. If anything binds, loosen the keep screws slightly, nudge the keep into line, then retighten.

DL-10Lubricate, test and tidy upAdd a light smear of oil or PTFE-based lubricant to the moving parts of the lock case and the keeps. Sweep up any dropped screws or debris. Test the door several times, locking and unlocking from both inside and outside, before you call the job finished.

1 each · Light general-purpose oil or PTFE lubricant

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1 each · Cleaning rag

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