Returned home from 3 week trip. I plugged in my 110 15amp home power and couple of days later my wife wanted to clean the interior so I turned on the electric water heater for her needs. A few minutes...
Your 7500 should run both AC and water heater with no issues. I am not sure what the 35 volts you mention is.
do you have power to the main circuit breaker panel. All most always you need to turn off all circuit breakers and back on to ensure they have not trip. Do you have your power switches turn on or checked.