A320 Center Tank
 

I read that the purpose for the center tank pumps to test after engine start is to scavenge any water in the center tank. Does anyone know where the water is drained? Any reference or schematics?

Short answer... Water is not drained overboard from the centre tank.

Water is drained manualy overboard on a daily basis by the mechanic/engineer. Or should be anyway!

Interesting. Would you know where exactly is the drain?

Open the panel in front of the Landing gears and look up !!

Never flown the A320 and not sure if its the same principal but the 747 has ejector pumps which suck accumulated water (and fuel) at the low point in the main tanks. The water is mixed with fuel from the Jet Nozzle and sprayed at the Boost Pump inlet there by removing water constantly, the engines are capable of running with these small amounts.

Perhaps the same principal is used while the A/C is still on the ground in the case of the A320 as stated.

Sorry chuzwuza, what I meant is it isn't dumped overboard in that fashion. But yes, 'should' be drained manually on a daily basis! Depending on if ones heating oil is running low or not...