28 year old electric hot water heater troubleshooting.

[staz70560]

I have a hot water heater that was installed when the house was built 28 years ago. Quit working out of the blue. It is plugged into a 230v 30A receptacle. There is 234V at the plug. I pull the access covers off and the reset button is in, every screw shows 115v when tested to ground, every screw shows 0v when tested across any other screw. The top heating element, when disconnected shows 13.3 ohms across the element.

Shouldn't it be showing 230V from the black at screw 1 to the red at screw 3? does anyone know what's going on here, and how do I fix it?

 

[GReynolds929]

There should be 240v across terminal 1 and 3. If not check the junction box on top of the water heater where the plug is. Make sure there is not a loose or burnt wire. At 28 years I would recommend replacing the water heater vs putting more money into a dying unit. Surprised it's lasted this long.

 

[Twowaxhack]

If it has 220-240v but still isn’t heating then it’s likely “ at least “ the top element is burned out.

 

[Ludington]

If it has 220-240v but still isn’t heating then it’s likely “ at least “ the top element is burned out.

Or the bottom, since that usually kicks on first

 

[Twowaxhack]

Or the bottom, since that usually kicks on first

If the bottom was the only element out the top element would heat. If the top element is out then the lower element would never heat.

Since the heater has no hot water then the upper Element is not firing at all.

Of course it could be the upper thermostat and other things. Sometimes there are multiple issues.

 

[Ludington]

If the bottom was the only element out the top element would heat. If the top element is out then the lower element would never heat.

Since the heater has no hot water then the upper Element is not firing at all.

Of course it could be the upper thermostat and other things. Sometimes there are multiple issues.

Ok, lesson time... (for me)
Normally the lower kicks on first, and the upper won't turn on until the thermostat from the lower is satisfied. So if the lower is broken, the thermostat would never switch to the upper. I think the exception to this is on a first fill (or when the whole tank is below temp)
I think I would be checking both elements.

 

[Twowaxhack]

Ok, lesson time... (for me)
Normally the lower kicks on first, and the upper won't turn on until the thermostat from the lower is satisfied. So if the lower is broken, the thermostat would never switch to the upper. I think the exception to this is on a first fill (or when the whole tank is below temp)
I think I would be checking both elements.

No, the upper kicks on first on a cold tank.
When the upper thermostat gets satisfied power is then transferred to the lower thermostat. If the lower thermostat calls for heat then the lower element fires.

If the top thermo never gets satisfied the lower thermostat will not get power.

 

[Ludington]

No, the upper kicks on first on a cold tank.

Oh, yes indeed. In my house, that upper never kicks on. If the lower goes out, I'll switch them and try to trick it to comming on to get started.. since you can't buy parts for mine anymore.
I guess the bottom line for op would be to check everything, since we don't know what state his tank is in.

 

[Mitchell-DIY-Guy]

If the tank isn’t leaking, aren’t the thermostat(s) and heating elements rather inexpensive compared to a full replacement? I mean, you could rejuvenate the entire tank by just replacing both elements and thermostats and who knows how long it would last!

 

[Ludington]

If the tank isn’t leaking, aren’t the thermostat(s) and heating elements rather inexpensive compared to a full replacement? I mean, you could rejuvenate the entire tank by just replacing both elements and thermostats and who knows how long it would last!

If you can get them, op is 28 years old... maybe not available.
My 24 year old, is no longer made or the parts

 

[staz70560]

Thanks to everyone who responded.

Anyway, you'll remember me saying that there was 0 volts from 1-3 but 115 on each leg to ground. On the top of the unit it shorted out and the red wire completely separated and was touching the black wire. Whoever installed the unit left an inch of wire-nut wire below each wirenut on the plug side of the connection. yYou can see moisture in the top pick, that's not water, it's rodent urine, I guess it's conductive. The unit is heating water again, but I think it's about time to replace the unit at my leisure, and not on it's schedule.

 

[TomFOhio]

Oh, yes indeed. In my house, that upper never kicks on. If the lower goes out, I'll switch them and try to trick it to comming on to get started.. since you can't buy parts for mine anymore.
I guess the bottom line for op would be to check everything, since we don't know what state his tank is in.

Try turning your lower stat all the way down and then turn the upper stat all the way up and see if the upper kicks on for you.