I have a city multi system comprised of 8 indoor ducted units (pefy-p25vmm-e) and one wall mounted mini-split unit serving a comms room. One of my ducted units is serving a room with a lot of natural light and as soon as the sun hits, the temperature runs away. Often a target of 19 will be set and the room will be sitting at 25 until long after the sun has gone down. During this time, the supply temp will match the room temp. It just won't cool. I don't feel this is due to too much demand because even with all other units turned off it is still unable to drop the supply temperature. The unit in the comms room will happily pump out -3 air even in the height of summer with all other units cooling as well. The room temp. thermistor is reporting correctly so it's not that.