I currently have three STBs (1 PVR, 1 old box and 1 new wireless box). I just got a 4K tv, so I was wondering if it's possible for me to replace the old box with the 4K one and still have access to my PVR?
You can't have two PVR devices on one account - there can only be one device on which shows are recorded.
The 4K Box will let you record in 4K...
Unfortunately, you will lose all the programs you have rfecorded on the Telus PVR, when you switch to 4K Box.