By Petra PaulsonThe "E8" message appears because your wireless receiver can't support the number of wireless zones that you've programmed into your Vista 15P or Vista 20P.Each Vista Panel has a different number of wireless zones it can support. This doesn't always match the number of zones supported by its corresponding wireless receiver. For instance, the Vista 15P supports 32 total zones, but only 26 of those are wireless zones. A wireless receiver must be installed in order for the Vista 15P to communicate with those wireless door/window sensors, motion detectors, and glassbreak detectors. If the 5881ENL receiver is installed, users can only access 8 of the 26 zones. The 5881ENM supports a maximum of 16 wireless zones. The 5881ENH, however, can support an unlimited number of zones. So, for users looking to reach the full 26 wireless zones in the Vista 15P (or the 20P's 40 wireless zones), installing the 5881ENH wireless receiver makes the most sense.
Once the new receiver is installed and properly assigned to the panel, the "E8" message should clear away.
Vista 10P Control Panel
Vista 21iP Control Panel
Honeywell 5883H Wireless Receiver