Troubleshooting guide
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.
Use this atlas to identify likely meaning and prepare for service. Shut off power, LP gas, fuel, or water when a listed appliance condition involves flame, gas smell, exhaust, generator shutdown, high temperature, moving jacks/slides, refrigerant, 120 VAC, control boards, repeated ignition failure, or a persistent lockout. Call the appliance maker, RV dealer, or a qualified RV technician for repair.
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.