I bet it's the fans somehow malfunctioning with RPM. If you can find which one is the culprit you should be able to find replacement fans for the unit pretty easily if you're willing to spend a bit to repair your miner as the S5 doesn't require high CFM fans to cool it aquedately.
I skipped from S3s to S7s, but some had a "disable alarm" checkbox in the web interface. If it exist, that might help, but I would seriously pause and see what the problem is. Perhaps take the fans off and plug them into a motherboard and see if they spin up, or at least verify they are still spinning freely.
This could also work if temps are okay on the miner. A box like shown below should be in the miner config page, just uncheck the beep option. Like VRobb previously mentioned, these two things shown below are closely related. If it doesn't work, post back with some temp readings.