Electric water heater questions

[kaw550]

I turned on the water heater at cottage for the first time yesterday. Nothing happenned.

I followed a online troubleshooting guide and I think I narrowed it down to a problem upper heater element. I did this with an ohm test but I am not up to speed with the different ranges on the meter. However the top element tested differently than the bottom... I do still have a question. Would there be voltage at the bottom element if the top one was bad? I read where the bottome element would not work if the top was bad but there was volatage at both.


The drain handle is plastic and rotates with the handle. I would like to plumb the drain through floor and use a ball valve to stop it. Does the plastic drain unscrew from the water heater? Can I swap it out? Do I need to use something made for high temps? I am trying to find an inexpensive solution to using a garden hose through the house.

 

[Jadnashua]

In most electric WH, it only runs one element at a time, and on a cold tank, it starts with the top one so you have some hot water fast, then switches to the bottom to get the whole tank hot. If the tank was not full before it got turned on, the element will overheat and burn out - it must be covered in water when power is applied. You have to run a hot faucet somewhere to get all the air out.

The drain valve does just screw in...you'd need either some pipe dope or tape (or both) to make it seal.

The elements must be ohmed with the power off, and disconnected. Zero ohms is a direct short...the element would be way less than 100 ohms.

 

[Sponsor]

 

[JerryR]

In most electric WH, it only runs one element at a time, and on a cold tank, it starts with the top one so you have some hot water fast, then switches to the bottom to get the whole tank hot. If the tank was not full before it got turned on, the element will overheat and burn out - it must be covered in water when power is applied. You have to run a hot faucet somewhere to get all the air out.

The drain valve does just screw in...you'd need either some pipe dope or tape (or both) to make it seal.

The elements must be ohmed with the power off, and disconnected. Zero ohms is a direct short...the element would be way less than 100 ohms.

Perfect explanation. The only thing I would add is, if the top element failed then the water will never heat up. The top thermostat is the primary controlling thermostat. It directs power to the top element with a cold tank. Once to upper portion of the tank reaches set temperature it only then directs power to the lower element and thermostat.

BEWARE, throw the circuit breaker to the water heater before measuring. Usually only one leg of power to element is switched and one always has 120 vac, unless circuit breaker is turned off.

JR

 

[kaw550]

I am not sure if it working before but I definetly turned it on before the air was purged out of it.

It's obvously safer to drain the tank everytime I leave but is it necessary? We are there every weekend but at this point there is no heat during the week.

Any idea what size fitting the drain would be? Do I need to use brass or can I use plastic. I have a ton of other stuff to spend money on.

 

[hj]

Your plastic drain valve MAY unscrew, but it is just as likely to "snap" off at the thread. It is 3/4" pipe size, so you need a 3/4" brass nipple and a valve. There are water heater 1/4 turn ball valves with a hose thread outlet and a cap on a chain to close it off.

 

[Jadnashua]

IF you turn the heat off in the cabin, then you either need to drain things, or leave the WH turned on - ice will wreck your day.