Electric Hot Water Heater Noises..Buzzzzz...

[DD716TED]

Recently our 5 year old 50 gallon Rheem Electric hot water heater has started making loud buzzing noises for brief periods of time.. It does it when no hot water has neen used... It will go away for awhile and then come back in the middle of the night? Am I looking at a water heater that is going bad or is there something much more simple? Of course the local Home Depot and Sears stores immediately recommend that I replace the heater but.......they are in business to sell new units... not give advice on how to deal with older units..

[LazyPup]

An electric water heater is really the epitome of mechanical simplicity and unless the pressure vessel is leaking there is really no reason to change the complete water heater.

There are no moving parts in an electric water heater and aside from an occassional very faint hissing sound which is produced by the water as it is being heated there really is nothing that would produce any sound if the unit is operating correctly.

The key here is there should be no noise associated with a properly operating electric water heater, however it is quite common to hear a buzzing sound such as you describe if there happens to be a loose or corroded electrical connection that is causing an arcing condition. Further understanding that arcing could be a potential fire hazard it would stand that the electrical supply to this water heater should be shut off and the water heater should be checked out immediately.

Per both the National Electrical Code and the Plumbing Codes if there is not a direct line of sight from the water heater location to the Electrical Service panel there should be an electrical disconnect in the immediate vicinity of the water heater. (An exception is no disconnect is required if the electrical service panel has a lockable cover).

If you have a service disconnect you should disconnect it, otherwise you should turn off the electrical circuit breaker before attempting any service to the unit.

I would srongly encourage everyone, whether a first time DIY'er or experienced professional tradesman to invest in a single probe voltage tester and whenever working with electrical circuits, motors or any electrical equipment housed in a metal cabinet, use the probe to insure the power is turned off. Far too often we find the breakers in the panel are miss labelled and just turning off the breaker labelled water heater does not guarantee the power is off. The alternative can be quite shocking!

With the power off you can remove the electrical service covers on the water heater and visually inspect all the wiring connections. Normally if arching is occuring you will see black carbon or slightly burned wire insulation where the problem is occuring. Be sure to check the top of the water heater where the primary electrical cable feeds the water heater. There is a service cover and inside you will find wire nutted connections between the water heater and the main power cable.

If you find a blackened terminal on one of the thermostats or heating elements it is indicating a loose terminal and in most cases it is a good practice to change that component.

If you do not see any burned or blackened connections the problem may be an internal problem in one of the thermostats and will require a complete diagnostic check with an ohm meter.

I have previously posted a complete step by step detail on how to use an ohm meter to diagnose an electric water heater control system.