The 120VAC is only circuit that uses a 'thermostat'
The 12VDC runs continuously ...no thermostat on/off control
The LP has Low, Medium & High settings....no thermostat control
IF AC and LP ON at same time....LP will overheat
If AC and DC ON at same time....DC will overheat
If LP and DC on at same time....BOTH will overheat
AC is only system using a temperature feedback to thermostat
DC & LP are just ON