Based on your other thread:
http://www.poolforum.com/pf2/showthread.php?12291
it's almost certain that you really did have water in the compressor, because you really have eaten up the heat exchanger with extremely low pool pH. This sort of damage is readily visible when you expose the exchangers. I wouldn't recommend attempting a warranty claim.

So, even though the service guy was a bit flaky with his HVAC knowledge, he was correct (even if by accident!) in his diagnosis of a heater destroyed by pool water that was very seriously out of balance.

Sorry!