Coleman-Mach 48000 AC cool-night evaporator ice-up
The Coleman-Mach 48000 AC owner manual says cooling during outdoor temperatures below 75 F can ice the evaporator coil when the thermostat is set too cold, stopping normal cooling until the coil defrosts with HIGH FAN and maximum air flow.
Owner-safe checklist
- Turn cooling off from normal controls if airflow drops or cooling stops during a cool, humid night.
- Set the thermostat midpoint between Warmer and Cooler when outdoor temperature is below 75 F instead of using the coldest setting.
- Run HIGH FAN with maximum air flow until increased or full air flow returns, then resume cooling cautiously.
- Clean owner-accessible filters and call qualified RV HVAC service if icing repeats or airflow does not recover.