Hi, I have mini-splits in my house and I set them up to run on high or just under high setting for fan and they change the heat sent from the outdoor unit to adjust the temp.  i don’t really use the auto fan setting.  i also have single-zone systems.

A friend has a multi-zone “multisplit” setup.  Two outdoor units with 5 heads on each.  He was complaining that it was always too cold, so I went over to try to help him.  He had been running the fan on AUTO mode.  I told him to turn the fan speed up to high on all of them and then set the temp. on the units so that he is comfortable.  I assumed that the heads would get less heat and maybe shut off the fan as they got close to temp or went over the set point too far.  If he has his units all set on high fan speed, it seems to run for 28 minutes and then shuts off for 2 minutes.  All of the head fans shut off and the compressor shuts off.  If he runs the fan speeds on AUTO, it keeps running and the compressor keeps running, but it feels too cold.  So, I told him to try turning up the room set point temp as high as he needs to to make the rooms comfortable.

Is it odd that when the fan speeds are all on high that the entire system seems to run on a 30 minute cycle?  What should happen if you set the fan speeds to high vs AUTO on a mult-zone setup?

He has two Carrier 38MGRQ48E outdoor units and then a mix of indoor units, such as 40MAQB09B—3 wall and 40MBFQ12—3 floor units