Fixing piano sticky keys using key easing
My U1 and U3 pianos all have new key bushings fitted. This is a small piece of felt within each piano key which holds the key tight to prevent too much sidewards movement and also helps keep the action nice and quiet. The new felt can sometimes need a little bit of bedding in so that it doesn’t interfere with the movement of the keys (causing them to return more slowly for instance). In other case, the process of delivering the piano to your home can cause the moisture content of these felts to change which can cause them to expand slightly and introduce some resistance to the keys.
This is not too uncommon but is thankfully very easily addressed by a process known as “key easing” where a technician will remove each key one at a time, compress the key bushing felts and then pop the key back in place. The result is a perfectly free and easy key again.
If your piano needs some key easing, there is a temporary measure you can try which you can use to free up a key. Waggle the key from side to side at the bottom, middle and top position. Try that a couple of times and see if it improves things. This might help you enjoy the piano until the technician next visits and can then perform a proper key easing process with the right tools.
The reason that your 1st tuning is delayed by around 6 weeks to allow time for these sort of issues to show themselves and then be addressed by the tuner during that 1st visit.