You must have the
SU2200XLNET inverter. That has a crest factor of 5:1 according to the manufacturer. That means that UPS can supply 5 times the RMS current resistive.
http://www.apcc.com/resource/include/techspec_index.cfm?base_sku=SU2200XLNET&CFID=23882586&C
FTOKEN=53254734
1600 watts / 120 volts = 13.333 amps. Mulitply that times 5 and you get 66.7 amps max output. If you do that, it won't be a nice sine wave, though.
In the US, 240 volts is 2 wires that are 120 each to neutral and 180 degrees out of phase to each other, drawn from a transformer that is center tapped to neutral. A 240v pump would use two wires (one from each side out of the transformer) carrying current to run and not use a neutral.
Most smaller 240v pumps have some provision to be run from 120v. Can you please post the model of your pump so we can check?
The proper lower limit for running a 240vac device in the US is 228v.
European 220v is similar to the US 120v, one hot wire, one neutral.
The SU2200XLNET can output up to 147v (user adjustable), so that won't do it alone.