Water Heater Mystery

[dfiler2]

Went out to the cabin yesterday to turn the water on and found that the water heater wasn't working. Checked voltage at the elements and both showed 122, pulled the wires loose and checked the elements for continuity and both showed good but i figured they must be "almost" fried. Picked up two new ones and changed them, no dice, still no hot water. Any ideas, can a bad thermostat allow a little voltage to pass through?

 

[Copymutt]

Sounds like you lost one leg. Could be a mechnical loss of one line. Ck. any wire nuts and all screw connections as well as grounds. Are all other circuits in the cabin working? If some are not you may have lost a transformer leg.

 

[NUTTSGT]

Did you check the actual voltage coming in to the heater ?

 

[dfiler2]

Good point, I will check the voltage at the panel, could also turn on the range, I suppose it could be a bad fuse at the pole. I did check the voltage coming to the heater, but if only one leg was working would it feed voltage through the element? There was a light that didn't work and just assumed it was a bad bulb. Will check that today, thanks much!

 

[klassenl]

but if only one leg was working would it feed voltage through the element?

Yes.

 

[Rock knocker]

One side of the elements is always hot, the upper thermostat is SPDT and the lower is SPST. If the upper is shot you may not get the circuit completed and not have either element functional.

 

[Rock knocker]

but if only one leg was working would it feed voltage through the element?

Yes.

But that answer is out of context. That won't show if the circuit is being completed.

Since one pole is unswitched, you'll always show 120v to ground on one side of the element. And if the element has continuity, you'll have voltage on both sides of the element. This need only indicate that the unswitched pole is in fact present.

My guess is the upper stat is out

 

[dfiler2]

The thermostat was fine, it was a 100 amp fuse at the pole, there was an extra in the panel, replaced it and all is fine.

Thanks, I'm sure that saved me a lot of time.

 

[Rock knocker]

The thermostat was fine, it was a 100 amp fuse at the pole, there was an extra in the panel, replaced it and all is fine

You should have also checked voltage at the infeed of the upper thermostat. That is the opposite pole than the voltage you measured at the elements.

 

[dfiler2]

You should have also checked voltage at the infeed of the upper thermostat. That is the opposite pole than the voltage you measured at the elements.

Would that have shown me anything? I checked the voltage where the main power was connected, however, I tested it by putting the probes into the wire nuts so I'm assuming the one leg was feeding through the thermostat. In hindsight I should have disconnected the wire nuts and tested the incoming voltage from the panel.

 

[Rock knocker]

Your initial tests only confirmed that one leg, in this case the un-switched pole, and was hot. You never tested the other pole do you didn’t really know if the problem was upstream from the stat.

 

[dfiler2]

Still not getting it and I would like to know if there was a different way i could have tested it at the heater to identify the problem. The thermostat was closed so I am assuming I would have shown power on both wires just as I did at the connection on top of the heater, I was testing from hot to ground.

Thanks, I am just trying to learn something, I'm not disputing what you're saying.

 

[Milton Shaw]

You need to test from hot wire to hot wire to see 240 volts. Test to ground or neutral will always show about 120 volts in the USA. England is 240 or so to ground or neutral so its really messed up for US going over there with appliances and the Hertz is 50 instead of 60 like here.

 

[dfiler2]

That makes sense, thank you, I will remember that.

 

[TheShrine]

At least you didn't call it a Hot Water Heater.

Good luck!