Hi,
In the kitchen at my work, they have a 'installed' pressure washer to do the floors. It is only rated for cold water, and there is a nearby sink with the typical hot and cold faucet handles, but the hot valve is removed. You could put in a hot and cold faucet, then turn on a mixture of hot and cold going to the pressure washer.
1400 PSI should be plenty of pressure. Your water pump should provide enough flow to the pressure washer. This should work fine to get off the bugs and stuff, without enough power to wash away the graphics (unless you get to close, so be careful).
Fred.
