Hii,

I have 6 package unit Trane brand 20 Tr and it was working just fine, then I install in each one a VFD to control the airflow ( High, Med, Low ) by changing the 2 stage thermostat to Fan coil thermostat Dx.
for the 2 first months, it was working without any issue, but recently all the units state freezing up.

Please support me.