Dometic 3102903.006 Quick Start Kit
The Quick Start Kit can be installed on all Duo-Therm roof mounted air conditioners and heat pumps. The Quick Start Kit will allow the compressor to start properly when operated on the Onan 2.8 Micro-Lite Generator as the 120 volt power source.
High ambient temperatures can affect the ability of the roof mounted air conditioner/heat pump to start on generator power.
See instructions here