Not letting the water out of barrel. making a humming noise

Are your water lines turned on? If so The humming noise you hear is the solenoid that allows water to enter unit. If that solenoid is stuck no water will enter but you will hear the humming noise.

it is buzzing because it is try to let in hot water and is activating the hot water inlet valve/solenoid

What sort of "humming" noise? Refrigeration systems rely upon vapor compression to operate -- meaning occasionally to maintain temp a compressor will kick in which can hum.

Air in line??
Add air vent
http://waterheatertimer.org/Repair-water-heater-valve.html#air

http://waterheatertimer.org/How-to-troubleshoot-electric-problems-with-water-heater.html#noise

Gene

Water Heater Timers Save Money

If you need further help, I’m available over the phone at https://www.6ya.com/expert/gene_9f0ef4df2f9897e7

sounds to me like the hot water solinoid is faulty

The humming noise is a defective coil that opens the water valve. When they weaken that begin to vibrate and hum because they don't have the strength to open the water valve. The replacement part number is 2188542. Let me know if you need any more help Sea Breeze
SITE=> http://servicepartstec.blogspot.com/

Both problems sound like motor has failed or is failing.

pump should be checked for restriction of movement,is there something blocking it?does the capacitor smell?if it does its blown(or meter check-more accurate),hope this helps

That sound is usually your icemaker calling for water. you can turn off your icemaker by lifting the little arm on the icemaker. As the icemaker calls for water the valve will be activated and will hum. This sound is usually not very loud. If your valve is making that much noise you may consider replacing the valve. The part number for you water inlet valve is #2315533 The retail price is $60.18 . I do have these on hand and available to ship out today if you need one. Please just let me know. You may also consider replacing your filter if your refrigerator has one. Thanks and I hope this will fixYa
Michael Anderson
Anderson Appliance
(865)945-3808

yo cna search ht e you tube sight for a visual refence to removing hte console/wrapper off the machine. soundsas if you have a bad motor coupling, this machine equivelint to the belt. youll find vids to replace that too