This is designed as a general guide and will apply to almost all multipoint UPVC locks commonly encountered. Hopefully it doesn’t sound too complicated, but in reality it is quite easy and if you take your time, and measure carefully you will achieve a rewarding result and save lots of money over getting a tradesman to do it.
(i) Firstly with the door open familiarise yourself with both the layout and operation of the lock and its keeps. The locking mechanism itself is normally branded on the long faceplate…look out for something like GU, FERCO, WINKHAUS, MACO, YALE, MILA, LOCKMASTER, COLDSEAL, AVOCET, ERA, SARACEN etc as this will be very important to identify your mechanism.
(ii) Secondly you need to identify what upvc lock you have in order to source a replacement. This involves measuring the mechanism. Many mechanisms will have a small horizontal line scribed across the faceplate at its centre point, normally just above keyhole level between the central deadbolt and the spring loaded latch. Use this point to measure from. If there is no line measure from the centre of the spring-loaded latch. Make a note of the locking points on the strip and measure from the line/latch to the centre of each of them. Write these measurements down.
– Next we need to measure the backset of the lock. You do this from the inside of the door and it is a very important measurement. You measure from the front edge of the locking mechanism to the centre of the keyhole.
– The final measurement you need is what is called the centres or ‘PZ’. This is the measurement from the centre of the keyhole (Take your measurement from the centre of the ROUND part of the barrel where the key goes) to the centre of the lever handle. It will normally be either 68mm, 70mm or 92mm.
– Finally measure the width of the long faceplate of the multipoint upvc locks it will almost always be 16mm wide. Occasionally it will be 20mm or 24mm.
– So now you have all the measurements you need, the backset, the centres, the faceplate width and the locking points. Coupled with hopefully the brand name of the lock you will now be able to source your replacement from Total Locks.
(iii) Thirdly you need to know the operation method of the lock. It is normally one of the following:-
– Lever operation. From the inside the doors locked by lifting the handle and then turning the key. It is unlocked by turning the key and then pushing down the handle.
– Auto locking or fastlocking. Lifting the lever fully locks the mechanism. It is unlocked by turning the key and then pushing down the handle.
– Key wind. On these upvc locks mechanisms they are locked by turning the key two or more times (hence key winding). They are unlocked the same way
(iv) REMOVAL. In order to change the mechanism you need to strip it from the door following these steps
– Firstly remove the handles, which will be held on by two or sometimes three screws on the inside of the door. Carefully store the handles and their special screws to one side. Their will be a spindle or spindles going from one lever handle through the door and lock to the other side. Note its orientation and then remove this also.
– You now need to replace the cylinder barrel. This is held in place by a very long screw fitted in the edge of the door…look out for a Philips screw on the faceplate of the upvc lock. Insert your key and then undo and remove the long screw. Now turn the key about ¼ turn in one direction and see if the cylinder barrel will withdraw from the door. If it won’t turn the key the other direction also ¼ turn and try again. The cylinder is fitted with a cam and by turning this back into the cylinder body you can withdraw the unit.
– Once the cylinder and handles are removed we can remove the main multipoint upvc locks mechanism. Undo all the Philips screws on the front faceplate, there will be several. Start at the bottom and work your way up. Note their positions. Around the central latch and deadbolt there will probably be two or three star shaped ‘torx’ screws….these hold the gearbox onto the IMM Screw Barrel main lock strip. DO NOT remove these whilst the main locking mechanism is still in the door.
– Once all the Philips screws are removed you should be able to carefully remove the complete long locking mechanism from the door complete with its centre gearbox. Be carefully as when it is out of the door it is quite bendy and easy to damage.
(v) Once removed you can lay the mechanism on the ground and check all your measurements again.
(vi) Now hopefully you have been able to source an exact replacement. Don’t worry if it’s too long as they are normally cut to size to suit the individual door with a hacksaw. If it is cut it to match your old unit.
(vii) Occasionally it may be that your unit s now obsolete which can entail replacement with a different similar unit or normally replacement of the gearbox itself. The gearbox is the large box fitted to the main locking mechanism which houses both the barrel and the handle spindle (the square hole/holes). It is normally the gearbox which fails as it is the unit that has to do all the work moving the hooks or rollers. Luckily on many units you can simply change the gearbox and fit a new one to your old mechanism. To do this remove the torx screws (T20 size) and carefully remove the gearbox from the strip. Note how it attaches to the mechanism and fit the new one in exactly the same way.
(viii) Refitting the mechanism is the reverse of removing. Locking mechanism first, then handles and barrel. Check it operates properly at each stage by testing the mechanism with the door open.