Find the circuit breaker that operates the timer.
Turn off that breaker.
Open the timer box.
Disconnect black wire from terminal 1 screw, and put wire nut or plastic tape over end of wire.
This will stop the timer, and then you can see what the timer is used for by watching what is not working.
Is the timer connected to a water heater?
http://waterheatertimer.org/Paragon-timers-and-manuals.html#4000If timer is connected to water heater, move black wire that was connected to terminal 1, and connect it with wire on terminal 2. This will by-pass the timer, and the water heater will be on all the time.
If you need new timer that makes less noise, then buy electronic timer.
Paragon 4001-00 is simple 120V timer, so replace with Intermatic EH10 120V electronic timer.
Amazon sells EH10:
http://www.amazon.com/Intermatic-EH10-Electronic-Heater-Indoor/dp/B000GHIPOAPlease add a comment for more detailed information.
I have extensive knowledge of these timers, and can help.
Also take advantage of fixya expert assistance live.
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Fixya is always less expensive than a service call.