Question about water heater element failure

Hello, About four months ago, I replaced one of the elements on my water heater (240V / 4500W per element - heater's about 5 or 6 years old). There are two elements on the heater, and the upper element seemed fine so I left it alone. Yesterday, the new element failed. I pulled it out and found a hole blown in the element. This time I replaced both elements and both thermostats. Can someone explain some things to me. 1. Why did the new element fail so soon? 2. Why are there two thermostats? 3. Should the lower thermostat be set at a different temperature than the upper one?
thanks
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

1 likely made in China, return it, it should have a warranty
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Andrew wrote:

I have a question. why did you replace all the parts when only one was bad?
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Maybe you should read it again?
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

It should be noted that the heater is very difficult to get to. It is difficult to explain just how hard it is, but it takes about an hour just to get to the heater. So I want to minimize the number of times I have to access the heater. The heater is a 6 year system, and it is around 6 years old. I figured it was a safe bet to replace everything.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Don't know the answer to that one. Bad element? Bad water?

If I remember the explanation correctly (somebody correct me if I'm wrong), it's a demand thing. Cold water enters the heater at the bottom of the tank, hot water exits at the top. Normally in times of low demand, the upper thermostat keeps the upper element off and power is passed to the lower thermostat, which switches the lower element on and off to maintain the water temperature.
If demand lowers the water temperature at the top of the tank sufficiently, the upper thermostat switches power to the upper element, which is closer to the hot water outlet, in order to try to meet the increased demand. When the upper thermostat shuts off, power is passed to the lower thermostat again.

I would think you would want them somewhere close to the same temperature. I don't imagine those bimetallic spring thermostats are very accurate anyway.
Jerry
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

I believe you nailed it 100% Jerry.

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Bad element? Element "dinged" during installation? Tank anode needs replacement?

Top thermostat turns on top element. When top of tank is hot, it switchs off, and sends power to bottom element. Bottom element turns that off when bottom of tank is hot.

I don't believe so.
It is probably a good time to check or replace the tank anode also.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

So bottom element failed again.
most likely the tank is slugged up, full of crud....
element cant transfer heat properly, overheats and blows bad area.
when it fails again buy a new tank and replace it.
might consider relocating tank to a easier access location.
is the tank are backfilled with all sorts of junk? thats happened here rooms packed with debris.
after finally pitching a lot of junk it felt good, and is easier to find what remains:)
we had so much stuff when we needed something it was easier to go buy new, which only added to the problem:(
anyhow good luck with your tank
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Site Timeline

HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.