Dometic Single Zone LCD heat-pump defrost cold air
Dometic Single Zone LCD thermostat instructions say heat-pump defrost can temporarily put the unit back into air-conditioning mode, causing cold air at the registers; it typically repeats every 25 minutes of compressor run time while outside temperature is below 42 F and above 30 F.
Owner-safe checklist
- Record outside temperature estimate, selected heat-pump mode, fan setting, and how often cold air appears.
- Let the automatic defrost cycle finish if the RV remains safe and warm enough.
- Use normal furnace or heat-strip controls when the heat pump cannot keep the coach warm.
- Call qualified RV HVAC service if heat-pump heating fails in moderate weather or defrost behavior does not match the manual.